runtime.onMessage.addListener with a Promise does not work in Chromium based browsers

[martonlederer]

I followed the example in the Mozilla Webextension docs (here) and it does not seem to work in Chromium based Brave browser.

I get a response from the background script right away, but it is null, no matter what i return. If the listener is synchronous, it works just fine.

Any tips, or is this a known issue?