Thread:Extension talk:UserAdmin/@Add user, can not create any account except a type whose ID is start with number/reply (3)

I just noticed from examining the .php code (specifically User.php -> isValidUserName) that the username is considered invalid if it starts with a lowercase letter (although evidentally starting with a number is fine). This is a MediaWiki restriction, not an UserAdmin extension specific thing.

Specifically this function checks for (and considers the username invalid if found):

the username is an IP address is an empty string (duh) contain slashes is longer than the maximum allowed username _doesn't begin with a capital letter_ (ding ding ding, though again numbers seem to be fine)