mr. oconnor says thats the counter balance shaft gear ,plate, and rubber buffers, just like the clutch basket has, as you see.
it is held together with 3 rivets, which let loose,
ken says he inspects and resets them on every motor he does if he finds them loose.
and that you got very lucky it didn't wipe everything out,
you need to pull that clutch basket and inspect that, and all gears for collateral damage.
you will need a new counter balancer gear minimum.
and of course a good flushing of everything (tranny too)
to remove all the shrapnel