Restructure source file tree.

[config] / buster / etc_files / user / opt / firefox / defaults / pref / autoconfig.js

// We set up AutoConfig according to <https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig>, see firefox.cfg comments on why we need it
pref("general.config.filename", "firefox.cfg");
pref("general.config.obscure_value", 0);