I think your question got cut off.

You want to know where the add-on is installed on your computer?

For plugins (e.g., Flash player), the exact location of the plugin is easily available. Type or paste about:plugins in the address bar and press Enter.

Extensions are more challenging to locate. Some will be in your currently active Firefox profile folder, but some will be in the Firefox program folder and others may be in locations specified in the Windows Registry.

Is this on the right track?

See also:

• https://developer.mozilla.org/en/Installing_extensions
• https://developer.mozilla.org/en/Adding_Extensions_using_the_Windows_Registry

• https://developer.mozilla.org/Gecko_Plugin_API_Reference/Plug-in_Basics#How_Gecko_Finds_Plug-ins

See also:

• http://kb.mozillazine.org/Uninstalling_add-ons
• http://kb.mozillazine.org/Uninstalling_toolbars