I've done some more digging around, and it now looks more likely that the culprit is the mappings in the file:
/usr/share/X11/locale/el_GR.UTF-8/Compose
which belong to the package "libx11-data".
I've done some more digging around, and it now looks more likely that the culprit is the mappings in the file:
/usr/ share/X11/ locale/ el_GR.UTF- 8/Compose
which belong to the package "libx11-data".