--customize-hook missing in man page
https://manpages.debian.org/testing/mmdebstrap/mmdebstrap.1.en.html does not mention the new
--customize-hook which seems super useful. Maybe also other new features not yet in man page?
That is actually a feature and not a bug. ;)
You will see in the source code that the documentation even exists already but is merely commented out so that it doesn't show up in the man page. The reason for this is, that the hook interface is still experimental. I'm still gathering experience with it to see whether it is actually useful for all possible use cases.
Also see this Debian bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=942761
this issue is fixed by commit 112c0a5a