What does this mean?

[KC13]

I'm starting to see this a lot on newer downloads in the Aircraft.cfg file: JABIndex=1

What is it for?

[FelixFFDS]

If it's what I think, you can delete. Basically there is/was a program that could catalog/hangar what you have in the aircraft folder, so that if you were gettin gFS top open slowly, as it checked all your add on aircraft files, you could create groups of models (say most flown, GA, Heavies, etc) and before openeing FS, you could load JUST the group(s) you were going to fly.

I thinnk that most people really use regularly a few planes and really clutter up the aircraft folder with little used models (and prototypes)... present company included....