Comment 4 for bug 1861262

@seb128 I'm not sure it's upstream. <https://bugzilla.mozilla.org/show_bug.cgi?id=371734> has been around forever and was marked as duplicate of the still open <https://bugzilla.mozilla.org/show_bug.cgi?id=296568> where it appears Mozilla doesn't want to do anything about it. The earliest ancestor of that file I can find in the source is from 2010 <https://bazaar.launchpad.net/~mozillateam/thunderbird/thunderbird.groovy/revision/115#debian/thunderbird-3.0.desktop>.