Hi

About:config is available in the Nightly version of Firefox for Android.

The about:about works and interesting shows about:config but when clicked on the message "cannot complete request".

Why is about:config not available?

Small correction to my earlier message, about:config is also available in Beta.

Although in the past is has been more powerful, virtually everything is now baked into the underlying GeckoView engine, with what's left being of risk to the browser if changed.

So about:config is a security risk? If that's the case Beta and nightly still allow about:config I would at least expect beta to also remove about:config.

I am not suggesting that it is a security risk, more that the average user would benefit little from it except to change settings that would need the app to be reinstalled with loss of data.