Bug 973530 introduced the option to remotely debug SeaMonkey by another Mozilla application (specifically Firefox, at a time when the devtools haven't been ported to SeaMonkey yet). Those options were exposed in the main Advanced prefpane. There is no match for "debug" in Help search, and information provided in Web Development Tools is sparse concentrates on web-site development. In addition to some general information on debugging, the options in the Advanced prefpane need to be explained.

Bug 1263925 has added a description in developer_tools.xhtml with link to the Firefox documentaion, thus it appears that all that's left to do here is to describe the prefpane options.