Free Pascal strings (and i assume Delphi as they are sometimes compatible) are pointers to the first character of a null terminated string with a header in a negative offset before the first character indicating the string's length, reference count and codebase.

AFAIK a "Pascal string" is basically another way to say "length-prefixed string" (as opposed to null terminated string) and Free Pascal (and Delphi) are like that (and they're Pascal dialects too, so their strings are literally Pascal strings :-P).