Where does “*भार्त-” come from?

*भार्त- (Vedic Sanskrit) comes from Sanskrit भृत, from Sanskrit भृ, from Proto-Indo-European bʰēr- — shiny, light brown.

Ancestry of “*भार्त-”, step by step

Step	Language	Word	Meaning
1	Sanskrit	भृत	servant
2	Sanskrit	भृ	to bear, carry, hold
3	Proto-Indo-European	bʰēr-	shiny, light brown