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

worst extention. doesnt even work.. i need to copy download link manually. Using this on ubuntu firefox browser.

Its very Good, Thanks