I like this extension, but it could be a bit better if you could choose which email address to forward emails to if you have any secondary addresses in your account.

Better yet, there could be the option to manually type the email address in, allowing you to choose whichever one you want. However, I understand if the developers don't want to add that feature because of the risk for abuse.

Also, if there is a way for Mozilla/Firefox Relay to tell me when a message that was supposed to be forwarded was blocked because it was too large, I'd like this extension/service even more.

I'm happy with how this extension is currently, but I still think it has some room for improvements.