What character set does it use? For example, can "O" and "0" considered different characters or same character, and are some letters/numbers not used? If so, then how many they say are possible is not quite that simple, since some might match (so they cannot simply be added together) and some might not be possible.
I was hoping “using TypeScript” was going to be more along these lines, i.e. using the type system as a constraint solver for some combination of homoglyphs that resembles a target string.
