This is the entry point to V$SESSTAT performance counter documentation.
There's nothing useful here yet.
Note that I do not intend to document every single statistic out there, but rather some more complex and less understood ones, which haven't been documented well enough in Oracle's documentation.
Right now I recommend to look into the "Statistics Descriptions" page in Oracle Documentation:
If you don't find what you're looking there, then you're welcome to request an explanation from me here