Debranding a z750A.

Hi I recently purchased a Z750A off of ebay and of course its ATT and I need it debranded.

I've done this before using d-client but it seems now we have a bunch of custom files on the d-client web site for the phone.

I guess the question is what are these ?
On the last phone I just picked the a2fs and the a2sw file and it worked like a charm.

I assume I can do this again. but I'd like to be informed of what these other options are also before I buy the logs.