Where does “brunatre” come from?

brunatre (English) comes from French brunâtre, from French brun, from Italian Bruno, from Medieval Latin brunus, from Frankish brūn, from Proto-Germanic *brūn, from Proto-Germanic brūnaz, from Proto-Indo-European bʰerH- — to pierce; to strike; brown.

Ancestry of “brunatre”, step by step

Step	Language	Word	Meaning
1	French	brunâtre	brownish
2	French	brun	brown; brown-haired person
3	Italian	Bruno	dark gray, almost black
4	Medieval Latin	brunus	brown, brunet
5	Frankish	brūn	brown, dark, shiny
6	Proto-Germanic	*brūn	—
7	Proto-Germanic	brūnaz	brown
8	Proto-Indo-European	bʰerH-	to pierce; to strike; brown

Every word from Proto-Indo-European bʰerH- →Every word from Proto-Germanic brūnaz →Every word from Proto-Germanic *brūn →