How do I open about:config in Firefox on Android? A lot of settings on Firefox for Android need about:config, but I cannot open it by typing in the address bar.
Here is a screenshot 15 seconds after I typed about:config in the address bar and pressed enter.

Here is a screenshot showing the version of Firefox on my phone.

What am I doing wrong?
about:config is disabled in builds other than Nightly
From this answer:

You can access about:config in the Nightly build of Firefox for Android, available from the Google Play store .