You can also look those up, atlthough they all either:
have no projects
have projects with little to no content
have projects that are so ancient that they can’t be loaded properly anymore, and raw JSON analysis shows that they have little to no content
(besides “.” obviously, and “-” will be another exception)
Yes, but they’re all taken, and they’re not like two-character usernames where they occasionally drop.
I was able to get my hands on one of those recently, although typically it’s just a thing where they’re so old that the people who owned them have graduated high school by now.
If you account for character counts where all usernames are taken, with either no name drops or very little name drops with high demand, a username must be at least three characters. Otherwise, the minimum is one character.
Imagine, someone with an old one-character username logs in and changes their username, but then THT changes the minimum to three characters so no one can claim it. That would be quite sad.