Where does FireFox store extension's data on macOS?

The /Library/Internet Plug-Ins folder contains plugins that can be used by any browser run from any account on your Mac.

Mac OS X assigns a unique process serial number (“PSN”) to all apps launched via GUI. It's used for identifying various processes and…

I believe it's the moz-extension+++ folders in the storage folder in your profile folder:.

In my computer (MacOS X 10.7.5, Firefox 16.0.2), they are installed in : /Library/Internet Plug-Ins Here is a list of files inside this directory.

The plugin folder is located on ~/Library/Application Support/Firefox/Profiles/[profile name]/extensions, but some plugins could be located in different ...

The data is located inside the profile in storage/default. You'll find directories called moz-extensions+++<some guid> there. Those are the ...

You can find the file in your Mac Firefox's profile folder in the extensions subfolder. Since many may be named with a GUID instead of ...

Most add-on data is stored in a folder in the Firefox user profile. However, some information is stored in the profile folder also.

Firefox extensions are stored in your profile directory under the 'extensions' subdirectory, in .xpi files. You can find your profile by typing ...

I believe it's the moz-extension+++ folders in the storage folder in your profile folder (C:-Users-[user]-AppData-Roaming-Mozilla-Firefox-Profiles-[profile]- ...