Baseboard socket plug replacement

So up in the attic guest room of our century home, there’s a baseboard electrical outlet that looks like a light socket (see picture below). I’m not sure what exactly to call it, and various Google searches don’t turn up anything like it (probably because I don’t know what it’s called). When we moved in, it had one of those screw-in adapters like people screw into actual light sockets; I removed that immediately.

I very much want to replace the outlet with something from this millennium, but I admit to being a little wary. I’ve successfully replaced old two-prong outlets with GFCIs before, but I’m not sure if this is likely to be significantly different. I do expect 15A knob-and-tube wiring, and I’m not expecting a ground wire, but I’m wondering if there’s anything else I should be ready for before I start in. Or if this is one of those “oh crap, dude, don’t go anywhere near that thing without a certified electrician with thirty years of experience!” situations.

What say you, DIYstack?