In xiphos's git, I added an explicit dependency on imagemagick which provides display. I do not think that adding support for gio is required for the time being, at least not as a Debian patch.
- Bug#969775: xiphos: please call "gio open $URL" ... Simon McVittie
- Bug#969775: xiphos: please call "gio open $URL&q... Bastian Germann

