Welcome news! There is substantially more documentation on python "scripting". The word scripting, here, does not mean that SaxBasic is covered in these documents, but it does mean that the kinds of actions one used to use SaxBasic for are discussed. There are two documents – one weighing in at about 150 pages, and another at 250. So this will be a big help!
They are both found under Help … Programmability
They are the SPSS Scripting Guide and SPSS-Python Integration package.