The dumpon(8) man page mentions debug.minidump and kern.bootfile, but does not document them. Also, machdep.dump_retry_count is not documented. I created a Phabricator review: https://reviews.freebsd.org/D32618
@Conrad, Mark do either of you have cycles to review this or know someone relevent folks who might?
As Mark mentioned in the review dumpon.8 is not the right place to document kern.bootfile, but the others should be. dumpon.8 should have a .Xr to the page with kern.bootfile's documentation.