i believe this is what you need https://www.partstree.com/parts/briggs-stratton-795403/
use the part number to look around and see if you can get a better picture of it to be sure.
Or it may be this one, https://www.partstree.com/parts/briggs-stratton-790703/
the first is listed as a linkage cover, the 2nd is listed as Control Cover.
EDIT
Though, looking at the picture again, it appears it was molded to the whole cover and is broken off, So look at Rivets post below.