It's there for installation of an Omega adjustable clasp, along with the necessary links to attach the clasp to the bracelet.
It'll be there a while; the clasp is on backorder.
Unfortunately, I did not have a single 20mm strap.
Called upon Art and Terry for something to use in the meanwhile.
I really lucked out that Art had an OD canvas set to go.

I chose the Toxic Admiralty from Terry's offerings.

The colors are "similar", but I like the way they work with the white dial.

Might not even go right to the bracelet when it arrives.