Nice one Rated 5 out of 5 stars

Good work indeed + two suggestions:
- Change the default format in {4} — {1} ({2} {3}/s) like the default Firefox one that you can see in "all downloads" window otherwise is not consistent.
- Ctrl +J toggles panel is nice but you must add an other shortcut for "all downloads window" like Ctrl + Alt + J for example.
Thanks.

This review is for a previous version of the add-on (1.1.1-signed). 

Sounds like I should make the format apply to the all downloads display too, if it's doable. I swapped the order because the string will get truncated if it's too long; losing the speed sucks but losing the end of "remaining" is no big deal. The Library view has tons of space, so it's not a problem there, but the extension's dedicated downloads window does hit this problem.

For the shortcut key, you can use Keyconfig to run "BrowserDownloadsUI();" (or maybe just do Ctrl+J -> Alt+S). Adding a new, configurable shortcut key in an extension sounds like a bit of a pain. (I agree it's a good idea, but I won't make it high priority, especially when Keyconfig is a thing.)