Not work in flatpak

[Naezr]

I put the files from the "Program" folder in the path "/var/lib/flatpak/app/org.mozilla.firefox/current/active/files/lib/firefox" and got this error:

[MrOtherGuy]

I can't say anything definitive, but that sounds like Firefox is able to read the defaults/pref/config-prefs.js but it cannot read config.js

Perhaps flatpak tries to load it from somewhere else than normal binary directory?

[Naezr]

I don't know, I tried replacing config-prefs.js and config.js with symlinks, but nothing worked. So I just uninstalled flatpak firefox and installed the regular package. I also tried to package fx-autoconfig in Appimage and the same error occurred there. One thing I can say for sure is that fx-autoconfig is not friendly with containers. It's not critical for me, I just wanted to let you know.

[MrOtherGuy]

I'm not sure about this, would need to dig about more stuff, but it kinda seems that autoconfig as feature (not specific to this implementation) just doesn't work with flatpak. In bug 1785278 a change was made that allowed autoconfig to work in snap builds - but it doesn't seem to apply for flatpak.

[dominichayesferen]

It's intentional - Mozilla made it so if your config disables the sandbox it is 'invalid' - removing the sandbox-disabling line fixes the error but obviously prevents the JS loading entirely.