For now, we have various spots for devtools preferences: http://searchfox.org/mozilla-central/source/devtools/client/preferences/devtools.js http://searchfox.org/mozilla-central/source/devtools/client/preferences/debugger.js http://searchfox.org/mozilla-central/source/devtools/shim/devtools-startup-prefs.js And also: http://searchfox.org/mozilla-central/source/modules/libpref/init/all.js#1034 all.js and devtools-startup-prefs.js look redundant? all.js is mostly meant for preferences that have to be used in server/actors as the one from client/preferences aren't injected on fennec. Ideally we would migrate all devtools preferences to /devtools, is devtools-startup-prefs.js a good host? Will it contain preferences that are specific to the frontend?