OKAY, so I can report my first developed APS film.
I adjusted a reel to allow for a 24mm film, between the 16mm and 35mm notches that was already there, by way of a fine saw and a file (9,5mm - 3/8" from the 35mm notch, took all of 5 minutes).
Developed the film in Caffenol, after Reinhold's formula CC-M, with KBr to get rid if chemical fogging, for 15 minutes @ 20 C. Developed as usual 30 sec agitation at first followed by 5 sec / minute, used 1% stop bath and normal fixer.
The film is still being in the last wash, but I had a peek and can see my normal, quite strong B&W negatives on the (previously) color film.
I don't have the faintest idea of what IS on the film, this is another funny story from E-bay, I bought 5 films outdated and the guy went at great lengths, explaining "i really know nothing about this", the usual SMART type at ebay...
Now when the films came one was already exposed - and frankly I couldn't care less, the bid was 0.99c, postage was more, and I used the film as my test vehicle, since APS films are normally automagically exposed right in newfangled automatic cameras, that adjusts exposure automatically and correctly.
Now I have a VERY valuable datapoint, allowing me to go on with my first roll and be dead certain I will have it developed right.
The only fly in the ointment was opening the pesky APS cannister, that baby fore sure cannot be reloaded!
But I heartly recommend grabbing all that APS film you can, shoot it and develop it B&W in Caffenol!