Which Gecko-based browser to choose for Android?

Published initially as a reddit post.

Much depends on what functionality you want.

There are three or four types of Gecko-based browsers, and one can have two or three, depending on desired functionality. In all cases, you'll have to switch off automatic app updates in order to prevent your device automatically moving to a version with less functionality.

If you want the latest and dark mode, there's Firefox or Fennec (the latter with a delay).

If you want automatic updates to most apps from the Google Play Store, and the latest Gecko-based browser, pick Firefox, and then Fennec or IceCat from the F-Droid app, where you can switch automatic updates off.

In this scenario, where you'd want to stick to a certain release, pick a version of Fennec F-Droid, and/or GNU IceCat. Fennec has more versions to choose from; IceCat has less versions, as it tends to stick to ESR branches.

If you want legacy/XUL add-ons, you might have to consider Firefox/Fennec 56.0 as the last version.

If you want the latest branch that still has about:config, pick version 68.x esr (extended support release). It has support for add-ons available at addons.mozilla.org that are no longer supported by the latest Firefox due to changes to the extension framework (yet again).

68.x esr also supports viewing local HTML files, as I haven't been able to do this with the latest Firefox.

Firefox 43.0 (really legacy) and older still support cookie prompting via extension, and has slightly better support certain other legacy extensions. But this is a really old version.