I thinking it is a foreguy anchor point. Just high enough to allow the hatch to be open for a spin hoist or drop without interfering with the guy.
The new J/22s at
Sail Newport last summer all blew out the vang attachment to the boom and replaced it with a similar unit ... they are stronger than they appear.
[[ Bill ... will have to get you out on a J/22 now that you have time on your hands this summer. ]]
