They are actually allowed on combining marks of ccc=0. We even define one such variation sequence for Myanmar, IIRC.
On Sat, Feb 1, 2020, 2:12 PM Richard Wordingham via Unicode < unicode@unicode.org> wrote: > Why are variation selectors not allowed for combining marks? I can see > a reason for them not being allowed on characters with non-zero > canonical combining classes, but not for them being prohibited for > combining marks that are starters, i.e. have ccc=0. > > Richard. >
