Ubuntu – Where is Firefox’s plugins directory


I know that there are extensive, "proper" methods for installing Firefox plugins. However, I would like to know where the folder is for linking shared-object (.so) files, such as libnpjp2.so and libflashplayer.so so that I can install plugins the "old-fashioned" way. In Firefox 21, I would have put it in ~/.mozilla/firefox/*[profile name].default/browser/plugins but that folder is no longer there. It keeps jumping around as Firefox changes. In about:plugins I still see all the plugins that I would have put there.

Can anyone tell me where the folder is? I already checked the folders in /usr/lib/firefox and /usr/lib/mozilla.

Best Answer

Please read the update at the end of this answer regarding changes in Firefox 52.

Acording to the Firefox developer documentation plugins live here:

  • Directory pointed to by MOZ_PLUGIN_PATH environment variable
  • ~/.mozilla/plugins
  • /usr/lib/mozilla/plugins (on non-Ubuntu 64-bit systems, /usr/lib64/mozilla/plugins might be used instead)
  • Plug-ins within toolkit bundles
  • [Profile directory]/plugins, where [Profile directory] is a user profile directory

Update for Firefox >=52

As of Firefox 52 support for NPAPI plugins has been dropped. All plugins living in one of the above directories are ignored, with the exception of Adobe Flash.

If you installed Flash with the flashplugin-installer package, it's loaded through a symlink in /usr/lib/mozilla/plugins that ultimately links to /usr/lib/flashplugin-installer/libflashplayer.so.

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