/usr/local/share/applications/waterfox.desktop contained a few mentions of firefox/Firefox. I manually edited the file to include: Name=Waterfox web browser Exec=waterfox %U Icon=waterfox Exec=waterfox -new-window Exec=waterfox -private-window (Things seem to be fine, with those changes, touch wood.)
(Not sure why auto-assigner didn't notify me.) Waterfox is using Firefox desktop file due to lack of a better source. Currently, it replaces some "Firefox" with "Waterfox". It seems I forgot to adjust executable/icon name via post-patch.
A commit references this bug: Author: jbeich Date: Fri Dec 8 02:41:30 UTC 2017 New revision: 455766 URL: https://svnweb.freebsd.org/changeset/ports/455766 Log: www/waterfox: fix exec/icon name in .desktop file PR: 224095 Reported by: Graham Perrin Changes: head/www/waterfox/Makefile