Hello Konrad,
I would like to confirm the same behavior on my end. This happens with every native messaging extension I tried, doesn't seem to be just some. Actually, it used to work, then after something updated in Guix it stopped working. The same for Firefox from nonguix. I have no idea how to debug this since Firefox apparently decided to print the most helpful message ever for any and every error in the native hosting! Sigh. That's why I haven't even reported it, because I wanted to share at least some information about it, but could find nothing. My only other idea was to look through the librewolf compilation log, maybe it will print a warning about a missing/wrong dependency etc. Regards, Rutherther
