Firefox is a great browser with a great philosophy.

Download: https://www.mozilla.org/en-US/firefox/

Source code: https://hg.mozilla.org/mozilla-central/

There are several Mozilla based browsers that are also worth checking out such as abrowser, icecat, and LibreWolf.

Extensions have significantly changed since Firefox Quantum. Some of these may not work, but may work in the future or with a legacy build.

Extensions can make Firefox based browsers highly configurable.

• DarkReader attempts to make dark themes for all websites. This breaks pages often, but can be much easier on your eyes. Can slow your system down.
• Stylus can customize CSS on individual pages or domains.
• Matte Black (Red) is a dark theme for the browser menu bars.

• JShelter minimizes harm caused by JavaScript. FSF Blog post about JShelter
• NoScript selectively blocks JavaScript by domain.
• uBlock Origin removes most ads and trackers from most webpages. This is reported to decrease your network traffic by about 17% which increases the speed of your entire network.
• Privacy Badger blocks tracking between websites and automatically builds your blocklist as you browse passively.
• HTTPS Everywhere goes to the https page automatically instead of http.
• AdNauseum blocks ads and clicks on all of the ads to confuse advertisers.

• KeePassXC-Browser communicates between KeePassXC to store passwords securely. I would suggest not saving passwords in your browser or using this extension, but this is preferable if you are too lazy to copy and paste passwords from KeePassXC.

• Privacy Redirect can redirect pages to AGPL alternatives such as Twitter to Nitter.
• LibreJS blocks JavaScript unless the they have LibreJS compatible license information. This actively control the licenses and freedom of your JavaScript while browsing. This breaks most websites that use JavaScript. See The JavaScript Trap for more information.
• Cloud firewall can block domains by their hosting provider. You could block all Microsoft and Azure sites for example.

• Video Downloadhelper allows you to download streaming videos from popular websites. This is very useful for archival, slow Internet connections, and preparing for presentations.

• New Tab Override sets the page that opens when you open a new tab. Great to enable before giving a presentation. Set it to about:blank for example.
• Cookie Quick Manager backup or restore cookies.
• Link Gopher extracts all links from a page.
• DownThemAll downloads files in bulk. If you have a list of links to files, DTA helps you download all of them with a few clicks.
  • DownThemAll-Anticontainer
• User-Agent Switcher changes the user-agent string that you send to websites.
• CORS Everywhere can enable CORS everywhere by altering http responses.
• Pinger checks a page for broken links.

Some websites use annoying techniques to lead the viewer towards agreeing to things they would not normally choose. Instead of agreeing or coming to a compromise, you can remove the annoyances manually.

1. Install uBlock Origin browser extension.
2. Right click on an element that you never want to see again like the cookie agreement on stackoverflow.
3. Click on Block element... option.
4. Verify the correct element is selected.
5. Click on the Create button to never see it again.

If the wrong thing is selected after choosing Block element... or only a piece of the element is highlighted, click on the Pick button and crosshairs will appear, hover until you have the correct item, click, and then click on the Create button. The escape key cancels the selection process.

Problem: Google Docs does not support copy and paste. Reason: This is a purposeful security implementation as all website could pull from your clipboard.

Solution: Set your URL bar to this address: about:config

Do a search for clipboard, and change these values to true:

clipboard.plainTextOnly
dom.event.clipboardevents.enabled