firefox Archives - Page 7 of 8 - Chipp.in Tech News and Reviews

Mozilla reassures users that it won’t kill Manifest V2 support in Firefox

Posted on March 17, 2024March 17, 2024 by Martin Brinkmann

Mozilla confirmed this week that its Firefox web browser will continue to support the extensions Manifest V2 next to the new version Manifest V3.

Google announced several years ago that it would move Chrome’s extensions manifest to a new version. The manifest defines the capabilities of browser extensions. Google’s initial draft drew the ire from users, privacy advocates, and developers alike. The company’s engineers made several adjustments to Manifest V3, which addressed some criticism but not all of it.

It now plans to end support for Manifest V2 extensions later this year in Chrome. Most Chromium-based browsers will share the fate. In fact, the only option to avoid this is to spend engineering time on reintroducing support for Manifest V2 in the browser engine after removal by Google.

Mozilla is in a better position this time. The organization’s Firefox browser uses its own browser engine, which gives it more control over its set of features. While Mozilla has been pushing Firefox towards improved Chromium compatibility in the past, it has made decisions in the past against this if it thought that it would be in the best interest of the organization.

In the case of Manifest V2 and Manifest V3, Mozilla published a statement about the future of Manifest V2 shortly after Google’s announcement regarding the change. Summed it, it confirmed that Mozilla would not follow Google’s implementation to the letter. Firefox would continue to support Manifest V2, and thus all extensions that relied on it, next to Manifest V3.

In other words, Firefox users would get the best of both worlds. Future compatibility with Manifest V3 extensions and also backwards compatibility to make sure that extensions continued to work.

Not all extensions can be ported to Manifest V3. Some may be ported, but with an impact to the functionality. Especially content blockers and other security tools are on the receiving end in this regard.

Mozilla reiterates its stance

With Google’s deadline to end Manifest V2 support in Chrome coming closer and closer, Mozilla published an update on its stance regarding the change. Mozilla confirmed that it has not changed its strategy at all.

While Firefox is supporting Manifest V3 extensions to a degree already, it will continue to support Manifest V2 extensions as well. Firefox continues to “support MV2 extensions for the foreseeable future” according to Mozilla.

Mozilla keeps a back door open, but you cannot really blame the organization for doing so. The organization promises that it will inform developers and users at least 12 months before making a a change in this regard, if it decides to re-revaluate the decision.

Closing Words

Firefox continues to support Manifest V2 extensions for the foreseeable future at the very least. It is too early to say if the decision will have an impact on the browser’s usage numbers. Once Google launches the change in Chrome, users with Manifest V2 extensions installed will notice that they cannot use these anymore.

These have several options, one of them is migrating to a browser that continues to support them. It will be especially interesting to see how content blockers behave after the changes land.

Now You: What is your take on the Manifest V3 push by Google?

Mozilla adds new languages to Firefox Translations

Posted on March 13, 2024March 13, 2024 by Martin Brinkmann

Mozilla’s Firefox web browser supports native language translations since Firefox 118 in desktop and Android versions of the browser. This feature, called Firefox Translations, supports additional languages now.

One of the main distinguishing factors between Mozilla’s implementation of a translate feature in Firefox and that in other browsers is that Firefox’s runs locally.

Translations happen on the local device. All that is required for that is the downloading of a language pack for each language. Google, Microsoft, and other browser makers use cloud-based translation services. The consequence here is that information is submitted to company servers. Google and Microsoft know about the text that gets translated. Not a problem for some, but if you value privacy, you may prefer Mozilla’s implementation.

Firefox Translations improvements

Firefox Stable supported a good dozen languages up until now. These were Bulgarian, Dutch, English, French, German, Italian, Spanish, Polish and Portuguese.

The Estonian language is added to the list of fully supported languages.

Mozilla added support for additional languages, but these are limited to being translated. In other words, Firefox cannot translate other languages into these languages yet.

The additional languages are Finish, Greek, Hungarian, Russian, Slovenian, Turkish and Ukrainian.

Support for these new languages is added remotely to Firefox, an update of the browser is not required. You should see the languages listed already on about:preferences#general under Translations.

Support for additional languages in development

Mozilla is working on adding support for additional languages to Firefox. Users who run development versions of Firefox gain access to additional languages or capabilities.

The focus is on European languages, with Persian (Farsi) being the exception.

Dev users get full access to Czech and Persian (Farsi). Additionally, support for translating Catalan, Icelandic, Lithuanian, Maltese, Norwegian (Bokmål and Nynorsk) are also available. Lastly, support for translating languages into Hungarian, Russian, and Ukrainian is also available.

Closing Words

Firefox’s translation feature supports many European languages already. Several are still missing, including Danish, Swedish, and Croatian among others.

Support for non-European languages is lacking severely at this stage. These still require the use of other translation services at the time of writing and the foreseeable future.

Now You: which translation service do you use? (via Sören Hentzschel)

Exclusive: Mozilla CEO confirms that Tab Groups are coming to Firefox

Posted on March 9, 2024March 9, 2024 by Martin Brinkmann

More than eight years after Mozilla decided to remove tab groups from Firefox, the organization confirmed today that tab groups will make a comeback.

When Mozilla launched Firefox’s Panorama feature, which introduced tab groups in Firefox years before Google implemented the feature in Chrome, it was ahead of its time.

Tab groups improve tab manageability by allowing users to put multiple tabs into groups in the tab bar. These groups may be collapsed to free up room on the taskbar.

While Mozilla did introduced Tab Groups before Google, it was Google that made them practicable to use.

Current implementations in Chrome and other Chromium-based browsers are easy to use. It is an elegant solution. Panorama on the other hand showed tabs of the active group only to the user.

Mozilla announced the end of tab groups in Firefox about nine years ago. The organization cited low usage, a lack of quality, and high maintenance costs.

Mozilla CEO confirms Tab Groups

This month, something remarkable happened. Firefox user Belfox published a letter to Mozilla CEO Laura Chambers. In it, they asked Chambers to consider adding a tab grouping feature to the browser.

Firefox lacks proper tab grouping support. All Chromium-based browsers support it, thanks to the shared codebase. Belfox noted that tab groups was the top requested feature on Mozilla’s Connect website.

Nothing happened for about a week, but then, Chambers replied to the user on the Mozilla Discourse website.

She wrote:

Hello! Thanks for reaching out. I have some good news! I checked in with the team, and they have prioritized the work and have a people assigned to work on it.

In other words; Mozilla’s CEO confirmed that a team is working on tab groups and that it is a development priority.

The response is remarkable. Not because of confirming that tab groups will (likely) come to Firefox. It is remarkable because it is the first time in a very long time that Mozilla’s CEO communicates directly with the community.

Not with a letter or blog post, but in a discussion.

Chambers confirmed that Firefox would become a priority at Mozilla again after taking over the reigns from Mitchell Baker. It seems that she is making good on the promise.

This direct interaction with the Firefox base could help bring management, developers, and users closer together again. It gives hopes to a community, of which no small part felt neglected in recent years.

Closing Words

Firefox is getting tab grouping support, which is good news for users of the browser. The CEO partaking in discussions about the browser and responding to user requests is even bigger than that.

Chambers remains CEO for a limited time only. A successor has not been found yet and it remains to be seen if the future Mozilla captain will follow her lead.

Mozilla is also working on bringing tab previews to Firefox.

Now You: do you use tab groups?

How to enable Flash support in Firefox

Posted on March 5, 2024March 5, 2024 by Martin Brinkmann

Flash? Is not that the technology that had so many security holes that it had to be put down? Yes and now. Flash was undoubtedly highly problematic from a security point of view. It was, however, also a technology that was widely used to create incredible applications and games.

Flash is dead and there is no option to install Flash anymore in modern web browsers. The technology lives on, however. Ruffle is an open source project that emulates Flash in modern browsers and on websites.

There are two main options here: websites may integrate Ruffle for Flash emulation so that games and apps may be played. The other option integrates Ruffle into browsers so that Flash content may be played even if the site has no Ruffle implementation.

Firefox is in an excellent position, as it supports desktop and mobile extensions. This means, that you may install Flash in Firefox for the desktop and for Android to regain Flash support. Ruffle is also available for Chromium-based browsers, but all major ones limit extensions to their desktop versions.

Microsoft is testing extensions support in Edge for Android, but it is not there yet.

Installing Ruffle in Firefox

It is not difficult to install the extension in Firefox. Just visit the official Ruffle website in Firefox and activate the “add to Firefox” option on the page to install the extension. Ruffle displays the permissions that it requires — access your data for all websites — and an add button to commence the installation.

Once installed, Ruffle will load Flash content encountered in the browser. If the site uses a Ruffle implementation it will upgrade it to the latest version, if that is not already used. If the site does not emulate Flash at all, Ruffle will load the Flash content so that it can be accessed. In other words, the Ruffle extension may also prove useful if the site uses Ruffle to provide access to Flash content.

Note: Ruffle is still a work in progress. Some games or apps may not work properly or at all because of that.

Using Ruffle to play Flash games

Once Ruffle is installed, Flash games should load automatically. This is regardless of whether the website the game is hosted on supports Ruffle or not.

Apart from certain games or apps that won’t work properly, Ruffle’s extension is also not capable of loading local Flash games in the browser.

Other than that, it is smooth sailing from this moment on. Finding Flash games and apps on the Internet is probably the hardest part at this point. Most gaming sites that supported Flash games in the past have installed Ruffle by now. The extension may still be useful on some of these sites, as it may load a newer Ruffle version that promises better compatibility and other benefits.

Firefox for Android loads Flash games and apps just like the desktop version once Ruffle is installed. It may be difficult to play them in the browser, at least on smaller screens, as the resolution may be tiny because of missing optimizations.

Alternatives

A few projects offer access to thousands of Flash games and apps. Popular ones are the Flash Games preservation project, Flashpoint, which had a size of more than 30 gigabytes back in 2018 already. It has grown to a size of 1.4 terabytes since then.

The archive has preserved more than 170,000 games and animations according to information on its website. Good news is that you do not need to download the entire archive but a smaller distribution. Games and components are then loaded on demand.

Another project is the Flash Game Archive. It is still maintained up to this point and includes a searchable directory of games on its website.

Closing words

Ruffle is an interesting option if you want to play Flash games or apps in your browser. While it does not work for all games yet, it is a valid option. Many Flash game websites have withered away since the end of Flash, others have moved on to support JavaScript games only.

Now You: have you played games online recently?

Mozilla adds translations support in Firefox for Android

Posted on March 3, 2024March 3, 2024 by Martin Brinkmann

Mozilla is porting the private translations feature of the desktop version of its Firefox web browser to the Android version. The organization introduced translations support in Firefox 118. A core difference between Mozilla’s implementation and that in other browsers is that Mozilla’s runs locally.

When you use Google Translate or Bing Translate, data is transferred to Google or Microsoft servers. It is processed there and then returned to the browser.

Firefox translates webpages directly on the device. No data is transferred to Mozilla or elsewhere. In other words, Mozilla does not know the text that you want translated nor the site it is published on.

Firefox for Android: first look at translate feature

Translate is only available if Firefox Nightly for Android at the time. Even there, it is not visible right away but needs to be enabled by users.

Here is how that is done:

Select Menu > Settings.
Open About Firefox.
Tap five times on the Mozilla logo on the page until you get the notification that debug is enabled.
Go back to the main Settings page.
Locate the Secret Settings menu.
Toggle “Enable Firefox Translations” to turn the translate feature on.

A new translate icon is now displayed in the address bar when you open a foreign language page.

Tap on the icon to get options to translate the content into another language.

Firefox Translate for Android: the options

The main translate menu lists the source and the target language only. You may change those and hit the translate button to get the page translated immediately.

A tap on the settings icon displays translate options. Here you may enable “always” or “never” translate options. These are:

Always translate a specific language. When enabled, Firefox will translate the language automatically when it encounters it.
Never translate a language. Blocks translate functionality for pages in that specific language.
Never translate this site. Blocks translate functionality on the current site, but not on others.

Firefox uses local language pack for its translates. These need to be downloaded once for each language and this happens automatically when you select the translate option the first time for that language.

You may download all languages immediately in the Firefox settings. Note that this version of the translate feature supports only the four languages English, French, Italian, and German. All language packs have a size of about 28 megabytes.

Closing Words

It is unclear when the translate feature is rolling out in Firefox Stable for Android. It is likely that this is going to happen later in 2024, but Mozilla has not announced its plans yet in this regard.

Since translations happen locally, it is privacy-friendly. There is one downside at the moment: language support.

The desktop version of Firefox supports just a few dozen languages at this point. These will all come to Firefox for Android, but it may take a long time before Firefox’s translate feature supports the majority of languages.

Still, Mozilla is bringing another requested feature to Firefox for Android. This helps close the feature gap between Firefox and Chromium-based browsers. Also worth to note is that Firefox supports features that major Chromium-based browsers do not support. Extensions support is a major one.

While Microsoft is working on bringing extensions support to its Edge for Android browser, it is not there yet.

How to remove an entire site from your browser’s history

Posted on February 19, 2024February 19, 2024 by Martin Brinkmann

This guide explains how to remove all history entries of a specific websites from the browser’s Google Chrome, Microsoft Edge, Brave, Vivaldi, Opera, and Mozilla Firefox. It should work in most other browsers as well.

All web browsers record the websites that you visit while using them. The browsing history serves two main purposes: to highlight previously visited sites when you type in the address bar, and as a record for the user to look up previously visited sites.

Sometimes, you may want to remove sites from the browsing history. Maybe because you do not need a record of the site anymore or want it to disappear completely from the browsing history.

All desktop browsers include functionality to do that. Problem is, it is not clear exactly how it is done. Opening the browsing history displays all visited sites, but there is no option to remove a specific site from the browsing history.

Clearing the entire history works, but it results in a loss of all records.

Delete a site from Google Chrome’s history (and other Chromium-based browsers)

Remove site from browsing history in Chrome

The general method of removing a site’s records from the Chrome browsing history works also in all other Chromium-based browsers. It works in Microsoft Edge, Brave, Vivaldi, Opera, and all other desktop versions of these browsers.

Here are the required steps:

Select Menu and then History > History in the browser. You may also use the keyboard shortcut Ctrl-H to open the history, or load chrome://history/ directly.
Use the search history field at the top to find all entries of the website that you want to delete. The best option is to type its domain name, e.g., chipp.in.
Scroll all the way down to the end. Chrome lists only some of the entries by default. You may also repeat the operation multiple times if there are too many records.
Now check the box of the last entry on the page.
Scroll all the way to the top.
Hold down the Shift-key and click the box of the first history entry. All entries are now checked.
Select the Delete option.
Confirm the deletion.

Here is how this looks in other Chromium-based browsers:

The process should work in all Chromium-based browsers. Most redirect chrome://history to “their” internal page protocol, e.g., vivaldi://history or edge://history/all.

How to clear a site from Firefox’s browsing history

Mozilla’s Firefox web browser supports a similar feature. It works differently, as it is not based on Chromium.

Here are the steps in Firefox:

Select Menu > History > Manage History.
Use the search field to find all records of the website.
Switch from the “Today” filter to “History” to see all records of that site.
Use the keyboard shortcut Ctrl-A to select all entries.
Right-click on the selection and select “Delete pages”. Note that there is no confirmation.

What about other records?

Deleting a site from the browsing history removes records of visits only from this database. Other databases may still store information about the site. There is the downloads history, which may have records if you downloaded files from the site.

Sites may also place content on the computer, e.g., as cookies or site data. These do not get cleared when you delete the browsing history.

How to delete other site records in Chrome and other Chromium-based browsers

It is relatively easy to delete site data and cookies in Google Chrome and other Chromium-based browsers.

Select Menu > Settings in the web browser.
Open Privacy and Security.
Select Site settings on the page that opens.
Click on “View permissions and data stored across sites”.
Use the search at the top to find a site.
Click on the trashcan icon next to it to remove it.
Confirm the operation with a click on the delete button.

Note: this removes offline data and logs you out of the site.

Do the following to remove the downloads history in the browser:

Load chrome://downloads/ in the browser’s address bar.
Use the search at the top to find all records of a site.
Activate the x-icon next to each to remove the records.

Deleting site records in Mozilla Firefox

You may also remove cookies and site data records in Mozilla Firefox.

Load about:preferences#privacy in the Firefox address bar. This opens the Privacy preferences.
Scroll down to the Cookies and Site Data section.
Activate the “Manage Data…” button there,
Use the search field at the top to find a specific website.
Click “remove all shown”. Firefox deletes the entry immediately without confirmation.

Here are the steps to clear all downloads from a specific site:

Select Menu > Downloads or use the keyboard shortcut Ctrl-J to open the Downloads interface.
Use the search at the top to find downloads from a specific site.
Use Ctlr-A to select all downloads.
Press the Delete key to remove all entries from Firefox’s history.

First look at Firefox’s new Tab Previews feature

Posted on February 8, 2024February 8, 2024 by Martin Brinkmann

Tab previews allow you to hover over open tabs in the Firefox web browser to get a preview of the page’s content. Mozilla added the functionality into Firefox Nightly this week. Reason enough to take a look at the feature.

Tab Previews are only available in Firefox Nightly at the time of writing. The feature is disabled by default, but you may enable it.

This is done by setting the preference browser.tabs.cardPreview.enabled to true on about:config. A restart of the Firefox web browser completes the process.

Tip: you may set this feature to off in Firefox Stable later on to turn off tab previews. This restores Firefox’s display of the page title and URL then when you hover over a tab.

How Tab Previews work in Firefox

Hover over any open tab in Firefox and you see a thumbnail of the page after 1 second. The snapshot displays a screenshot of the top of the page. In other words, it ignores the actual position on the page.

It may look cut off as well, as you can see on the screenshot above. Still, hover over any tab and you do get a preview of the page.

Tab previews is a handy feature at times, especially if you have multiple tabs with the same title open. Think ten eBay auctions that have similar titles.

The 1 second delay is set by Mozilla. There is a preference that supposedly changes it, but it does not seem work right now. Check browser.tabs.cardPreview.delayMs on about:config to change the delay.

Comparison to Google Chrome

Firefox is not the only web browser that introduced support for tab previews recently. Google’s Chrome browser displays tab previews as well now in the Stable version.

Hover over any tab in Chrome and you get a screenshot preview of the tab. Google displays the same information as Firefox plus a tab’s memory usage.

There is one difference though. Firefox displays a screenshot of the top of the webpage all the time. Google Chrome, however, displays a screenshot of the actual position on the webpage.

It is possible that Firefox’s tab previews feature will also support this in the future. It is in development and it may change in the future though.

Closing Words

Not every browser user likes tab previews. It should be easy enough to turn these off in Firefox once they land in stable.

Now You: tab previews, yay or nay?

Firefox 122 for Android launches with secret local add-on install option

Posted on January 29, 2024January 29, 2024 by Martin Brinkmann

Mozilla released Firefox 122 for the desktop and for Android a few days ago. The desktop release was a light release. The highlight was a new -.deb package release for Linux users.

The Firefox 122 for Android release, on the other hand, introduced several improvements that are noteworthy. The official release notes list just a few of them.

The new mobile version of Firefox is already available. Mozilla lists just three of the improvements on its website:

The option to set Firefox as the default PDF reader on Android.
Support for Global Privacy Control. This is off in regular browsing mode by default, but users may enable the feature under Settings > Enhanced Tracking Protection > Tell websites not to share & sell data.
Firefox reports Android 10 as the operating system to reduce “user fingerprinting information” and “website compatibility issues.

Global Privacy Control may require an explanation. This relatively new initiative aims to move user consent from websites and services to the browser. It informs website operators that the user does not give it the right to sell or share personal information.

How to enable local add-on installations in Firefox 122 for Android

Mozilla changed its mind in regards to add-ons support. For some time, Firefox Stable for Android supported only a few dozen extensions. While these were some of the most popular add-ons for Firefox, it limited users significantly.

This changed last year when Mozilla unlocked full extensions support. Over 700 extensions are now available for Firefox.

Tip: check out these tips for extensions use in Firefox for Android.

A new change is the ability to install local extensions. It is a great option for developers and to integrate extensions that are not available officially yet.

It is necessary to unlock the Debug menu first. This is done by opening Menu > Settings > About Firefox. Tap five times on the Firefox logo on the page that opens to enable the Debug menu.

A new “Install add-on from file” option is added to the browser’s main settings page afterwards.

Select the option to display a file browser. Use it to pick the add-on that you want to install. Note that it needs to be stored locally already before you use the functionality.

Other improvements in Firefox 122 for Android

Sören Hentzschel published a list of additional features that Mozilla did not mention in the release notes. These are:

Cookie Banner Blocking supports Consent Management Provider (CPMs). This adds support for several widely used solutions to display cookie banners.
Audio Sandbox is now also active in Firefox for Android.
Firefox users may report add-ons to Mozilla now.

Closing Words

Firefox 122 for Android improves support for extensions further. The option to install add-ons from file in the stable version improves development and gives users of the browser additional options.

Not everyone needs these, as the list of add-ons grows significantly each week currently.

Now You: do you use Firefox on Android or another browser?

Firefox for Android Extensions: 5 Tips

Posted on December 16, 2023December 16, 2023 by Martin Brinkmann

The road towards a full extension ecosystem in Firefox for Android was long and difficult. Mozilla Firefox for Android supported the majority of desktop extensions for a long time. This changed when Mozilla switched from Firefox’s own native extensions system to the one used by Google Chrome and Chromium.

Suddenly, users of Firefox for Android could install just a handful of extension. While the selection included popular extensions, it reduced the extensibility of the browser significantly. Development editions were not as limited, but it still was complicated to install extensions that were not selected by default.

Mozilla did add more extensions over time to Firefox for Android, but the selection remained limited.

This changed with an announcement earlier this year that Mozilla planned to unlock extensions in Firefox for Android. An update on December 14th, 2023 brought the much awaited change to the stable version of Firefox.

Firefox users may now browse more than 500 extensions for the Android version of the browser already. This is a ten-fold increase over the situation on December 13th, 2023.

While that is still miles away from the thousands of extensions for desktop Firefox, it is a great start and something that sets Firefox apart from its main competitors. Chromium-based browsers, including Google Chrome, Microsoft Edge and Vivaldi, do not support extensions in mobile versions.

Firefox for Android Extension Tips

Here are five extensions that I use in Firefox for Android. They improve the browser in several meaningful ways. Feel free to post your extensions in the comment section below and let me know whether you agree or disagree with my selection.

A remark on YouTube. I use a third-party app to watch YouTube, and don’t need any extension therefore in Firefox for that. If you watch YouTube videos in Firefox you may find ad skipping extensions and others useful.

Extension 1: uBlock Origin

There is no doubt about this, uBlock Origin is a must have extension for Firefox for Android. It blocks advertisement and tracking, which leads to all kinds of positive effects: faster page load times, improved privacy, improved security, less distractions, improved battery load and performance.

Extension 2: Bitwarden

Bitwarden is a popular password manager. While there are others, it is open source, available for various platforms and free to use without any impairing functionality limitations. The paid version is relatively cheap at $10 per year and highly recommended to support the project.

Extension 3: Single File

Single File adds support for saving entire webpages as a single file on the Android device. It is useful to save a local copy of a webpage either for safekeeping or offline access. It is also useful if you fear that the content may change in the future.

Extension 4: Dark Reader

Dark Reader brings a dark mode to any website, even those that don’t support it. It comes with lots of customization options to make dark mode work exactly the way you want.

Extension 5: Reddit Annoyances

Reddit Annoyances deals with Reddit’s attempt to get users to use the app instead of a mobile browser. It blocks those, which makes browsing Reddit in Firefox much nicer. One reason for using Firefox is that it will block ads on Reddit, if you have installed a content blocker. Only useful if you visit Reddit, e.g., from search results.

Also useful in this regard: Old Reddit Redirect.

Now You: do you use extensions in mobile browsers?

How to block Firefox from importing OS Certificate Authorities

Posted on October 26, 2023October 26, 2023 by Martin Brinkmann

Mozilla’s Firefox web browser maintains its own root certificate store by default. The browser uses these as “trust anchors” and the functionality is essential for making sure that only trusted SSL/TLS certificates are used by the browser.

Starting in Firefox 120, Firefox will automatically trust operating sysdtem certificates installed by the user or an administrators.

The beta release notes offer the following explanation:

By default, Firefox now uses TLS trust anchors (e.g., certificates) added to the operating system by the user or an administrator. This works on Windows, macOS, and Android, and it can be turned off in the “Privacy & Security” section of Firefox settings, under “Certificates”.

Administrators may add certificates to the operating system for a number of reasons. Some applications and devices may require them to work properly, and they may also be required in development environments. Antivirus solutions on Windows may try and register with Firefox to monitor data.

Blocking Firefox from trusting OS certificates

Firefox block third-party root certificates installed by the user

Firefox users may disable the functionality in Firefox 120 and newer versions. It is enabled by default. To modify this setting, follow these instructions:

Load about:preferences#privacy in the Firefox address bar to open the Privacy settings.
Scroll down to the Security section.
Locate Certificates there.
Remove the checkmark from “Allow Firefox to automatically trust third-party root certificates you install”.

You can undo the change at any time by checking the box again.

Another certificate preference

Firefox supports an Enterprise root preference already. When the browser runs into a TLS connection error, it will enable this Enterprise Roots preference automatically. This imports “any root certificate authorities” that users or administrators have added to the operating system.

Firefox tries to connect again to the site that threw the error. If successful, Firefox will keep the preference enabled and thus also the imported certificates.

Here is how this automatic behavior gets disabled:

Load about:config in the Firefox address bar.
Click “Accept the Risk and Continue” if the warning page is displayed.
Search for security.certerrors.mitm.auto_enable_enterprise_roots.
Change the value from True to False with a double-click or by using the button.
Search for security.enterprise_roots.enabled.
Change the value from True to False.
Restart the Firefox web browser.

Closing Words

Most Firefox users may want to keep the default as these are designed to minimize connection errors and issues. Users who want to be in full control may disable the functionality, on the other hand.