Keyboard shortcut to chose and fill in credentials

I’m very satisfied with the browser extension for Firefox Browser. I like navigating the web via shortcuts, so I was wondering whether there are shortcuts for the extension to fill in credentials to log in webpages?

I think someone added Alt+Shift+0 as keyboard shortcut for to open the extension.

But it’s not possible to navigate within the extension popup. Maybe that can be changed? Feel free to make a pull-request for the extension to add this.