Source: rxvt-unicode Version: 9.22-8 taffybar is unable to find the urxvt icon unless I happen to start taffybar in /usr/share/pixmaps.
I believe this is because rxvt-unicode.desktop specifies the icon file as neither a name that can be found in a GTK theme directory nor an absolute path. This is based on a reading of the .desktop spec[0] and inspection of all the other files in /usr/share/applications . [0] https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html