What is attached to this spigot and how to remove
I learned a little about these doo dads this year when the two on our home started leaking after the winter freeze we had in Texas. The rubber grommets inside both went bad. After trying to get them off with no success, I took a picture and headed down to my favorite plumber dude on isle 9 at our local Home Depot. He laughed and smirked a little, then told me the backstory aaannnnddd... the trick to getting it off. Apparently, the home builders - after having a few too many of these stolen from homes during &amp; after home builds - started enforcing the installers to grind the little locking screw off so that they could not be removed without a bit of work.
That little rusted over rivet spot, that’s where this screwhead used to be.

I also learned that there are two options you can buy when you need to replace one of these. You can buy the commercial grade that cost on average $30 OR you can get a non-commercial grade for less than $10. According to isle 9 plumber dude, they work the same. It’s like buying a Polo; does that little embroidered horse help with function?
So I went with the non-commercial $7 one, and they’re working great. Here’s how I got them off; you’ll need a drill bit that is made for going through metal. Place the drillbit on the spot where the screw was ground off, slowly drill out the old screw. Emphasis on slowly because you don't want to screw through and into the threads on the spigot. As you drill, take breaks to stop and see if it will come off. Eventually it will.