What are these used for?

Documenting my rig for winter work and a new mainsail, and it's like a box of chocolates...

Here is the gooseneck fitting from below - what are the two fairleads for? (Cunningham maybe?)

Another mystery item, this shot from the bottom of the boom.   The swivel padeye is the vang attachment.  What was the the cleat mounted forward of that used for?
Does anyone know who manufactured the padeye itself?

The next two show why it is a good idea to inspect the rig!  End of boom casting fracture, and mainsheet attachment rivet failure.