Excerpt from change request document:

As best as I can tell, these refer to the same language from two different sources. The bgk information seems to have originally come from J-O Svantesson, whereas the Buxinhua information is originally from the Encyclopedic Dictionary of Chinese Linguistics. "Bit" and "Buxin(g)hua" appear to refer to the same small language in Yunnan province's Mengla county which Chinese linguists (e.g. Shearer & Sun 2002) classify as Khmuic. As bgk is linked to speakers in Laos, it seems simpler to retire bxt.