It's hard to say without seeing the whole thing (Is it a single or a double door? Two single doors? etc.).

On the surface, I'd bet they had bowing/flexing issues (or wanted to prevent them) because the wall wasn't beefy enough.

It’s a two car garage door.

Why do you ask?

I would like to get them removed so I can get the garage door vaulted. I’ve read a few forums and they seem like the were originally need to keep the wall square while framing them and I don’t see how they could be structurally need now that the roof is on.

Well, two things:

1. If they really are temporary, somebody went through a lot of trouble cutting sheetrock to go around them rather than just knocking them out. I bet they aren't temporary.

2. By "vaulted" do you mean that you want to curve the top of the opening? You can't do it. The wood over the doors is the header--it's structural--a solid 2x12 from the looks of it. You don't have anything that you can cut away to vault the opening without risking collapse..

Don't touch anything without consulting a structural engineer first. Seriously.