Wwstage-driver-leg byte identity gets one owner. The three carriers'
content identity is already blanket-owned by their r815_/r940_/r951_
corpus twins via test-data-byteid; their only non-redundant assertion
was the ww_ww driver leg, which 989_lib_byteid's 43-unit sweep covers
apart from the zero-dep root-only edge — folded in as a new probe row
(44 units). r940 fixture comments re-cited off the retired carrier.