This probably isn't mostly about password generation rules, but rather about how to fill the forms, e.g. what's the user name field named, etc. (Otherwise why would it be called "AutofillQuirks" and not "PasswordRequirements"?)
Overall the file does appear to contain various autofill quirks, but the expanded dictionary in the screenshot is literally named “PasswordGenerationRequirements”. It’s definitely about password generation rules.
Good point, but in the photo, the expanded dictionary property in the property list is “PasswordGenerationRequirements,” so it’s most likely all of the above.