xdg-utils use XDG_DATA_HOME as a destination of desktop-related files, like .desktop, icons, etc. See the port here as an example: https://bugs.freebsd.org/bugzilla/attachment.cgi?id=188561&action=diff
See the port here as an example: https://bugs.freebsd.org/bugzilla/attachment.cgi?id=188561&action=diff It has to move icons, etc from WRKDIR.