What ar the allowed functions in expression questions in survey

Is there a list somewhere of what are the allowed functions in Expression only questions. There are 7 listed as allowed with an ‘and others’ when you click on the ? above the Expression input field.

Specifically I’m looking for a way to randomly assign participants to groups where they are not coming from Sona but from a social media posting. So far that requires user input in a previous question to give some sort of varying pseudo random input, eg what are the last 4 digits of your phone number which I then do a {PhoneNum} %3 +1 on. But obviously it would be a lot better to not require a previous input and use something like The Seconds instead.

I’m aware random group assignment is on the way and am looking for an interim solution so if anyone is reading this after Jan 2023 the specific problem should be gone