Doesn't seem to capture many/any downloads, "options" button does not work; I'm not sure if any of it works. (I'm using the latest versions of Windows 10 and Firefox.)

1 star simply because it doesnt have video streaming download integration like IDM.

It seems that this extension is broken for Firefox running from snap in Ubuntu 22.04. That is unfortunate, as FDM is otherwise a nice software.
When running the extension, it fails to connect to the host process, only showing 'Loading...'. This is probably caused by security restrictions on localhost.

Works just right