The class designations with big letters are on the bike. "Cat 1" means "motorcycles propelled by the action of one wheel in contact with the ground." There are other categories for bikes with two powered wheels like Rokons and bikes with tracks instead of wheels.
"Group A1" is for "solo motorcycles." These are "2-wheeler bikes making one track on the ground." There are other groups for sidecar bikes and cycle cars like Morgans.
"Division B" is "Partially-Streamlined." Naked bikes are in Div A and full streamliners are in Div C.
"Type 1" means "Internal combustion, spark ignition, naturally aspirated."
"Class 10" is for "over 750 cc to 1000 cc"
"(2 Cyl)" means the twins class with Honda Superhawks, BSA A-65's,etc. Abbreviations like APS-AF would not mean a lot to a guy in Indonesia or elsewhere. The way the FIM does it makes sense from an international perspective.
One big difference between FIM and other organizations is a two hour turn around time between the down and back runs. This means a fellow or lady has to be pretty organized. Those two hours pass pretty quick.
Our team ran and set records on a couple of bikes in the AMA modified partial streamliner - production engine class, MPS-P. Production engines were made illegal for modified or altered partial streamliners. The engine was changed to make it altered so it could run in MPS-AG or APS-AG. Then, production frames were made illegal for MPS or APS. This was getting silly. Now the bike had no AMA class to run in. It has a Triumph frame. The FIM rules are much more stable. I can be fairly sure that what I raced last year can be run this year. It was hard to do this with the AMA.
The FIM rules give builders more latitude. Electric motor driven forced air induction would be legal in Type II. A bike like mine with lots of streamlining and a production frame is illegal in AMA.
This explains a little bit about the FIM and why it makes sense for this guy to race in it.