Only works for direct URLs. Continues to pass on the default UA for any page resources (JS, CSS, images, etc.) Sadly it's now how it is supposed to work.

When I try to log in to discord.com, the screen turns blank and I can't get in.
If I turn off this add-on I can log in, so I think something must have gone wrong with a recent update to the add-on.

It works nicely on desktop, but I can't install it on android. Can you mark it compatible with ff for android too?