ST MakeGuid() returns a 16 byte string of Random letters.
uppercase letters and digits (so 36 possible characters). This would give 7.958661109946401e+24 possible combinations (a large number!).
StringTheory doesn’t contain these but conforms to version 4 UUIDs.
https://www.rfc-editor.org/rfc/rfc4122#section-4.1.3
which is “randomly or pseudo-randomly generated version specified in this document.”
because this can contain all the binary characters (rather than just a selection from the 36 letters and digits) there are a couple of formatting options to show in hex (32 chars rather than 16) and optionally add hyphens and brackets.
it uses GuidEncode for the formatting:
https://www.capesoft.com/docs/StringTheory3/StringTheory.htm#stGuidEncode