Thanks! I was about to post just that question. I haven't found this elsewhere in the documentation or forum, just references to a few of the levels by number with no explanation of what is being logged. It might be helpful to have it on the http://www.fop2.com/documentation-insta ... ommandLine page.
BTW, in the --debuglevel description on that page, it mentions the command line option overrides the value in fop2.cfg. I didn't see any comments for debuglevel in my fop2.cfg, and putting in debuglevel = n also didn't seem to work. I'm running version 2.22.