I've seen a couple related questions, but they're either Windows-specific, or out-of-date — my FireFox profiles/BLAH.a2rad folder doesn't include a browser-extension-data subfolder.

A couple specific examples:

  • The configuration for the AutoPinTab extension, including URL regexes
  • The (rather complicated) configuration for TreeStyleTab, including custom CSS etceteras
  • The configuration for Request Control

... all of which are too complicated to manually copy over setting-by-setting when switching to a new machine, and don't seem to get synced by FireFox Sync.

Where can I find all configuration for all extensions, so I can add them to Syncthing and have them automatically sync between my machines? I've ripgrepped through the Profiles folder, with no luck. What am I missing?

  • They're probably mixed in with web sites' local storage.
    – Daniel B
    Dec 26, 2021 at 17:56
  • Why didn't you just migrate the machines?
    – Tetsujin
    Dec 26, 2021 at 18:08
  • I’m unsure what you mean by that — I’m only aware of FireFox Sync, is there a separate migration feature? Dec 26, 2021 at 19:49
  • And more generally — I’m looking to sync them using my existing sync/backup system (Syncthing), not something external and manual that I have to think about separately. Dec 26, 2021 at 19:50
  • MacOS can migrate all data from your old Mac to the new - support.apple.com/en-gb/HT204350 Then iCloud can keep them both in sync. No 3rd party solutions required.
    – Tetsujin
    Dec 27, 2021 at 11:16

2 Answers 2


Firefox extension settings are indeed stored together with regular web sites’ local storage data. They use the same mechanism, after all.

The data is located inside the profile in storage/default. You’ll find directories called moz-extensions+++<some guid> there. Those are the extension settings. They are, however, not human-readable. This answer on Stack Overflow has more details on the format.

You can find out which GUID corresponds to which extension by going to about:debugging, then This Firefox. On this page, check the Internal UUID.

I do not expect these files to be syncable in any way. Instead, you should contact the extension developers. If you feel that some settings should sync, do tell them. They can select whether to use local storage or sync storage.


On my M1 Ventura it is on /Users/YOURUSER/Library/Application Support/Firefox/Profiles/MYPROFILE/extensions. But as stated by Daniel B it is not human-readable.

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