Interesting thing I wanted help pondering...

it looks simple, but it might throw some off...

/?b_n/

question: Does or can it exist, why or why not?

compared to say [found in Khmer]

/m=?b/

+++++

Since I was looking at a certain SC

/mbab/ > /mb@b/ > /m?b/ [which would either break that NC cluster to nasalize the
implosive, or to become a syllabic]