LD_AUDIT is another one worth knowing about (though I admittedly use it less often than LD_DEBUG) https://man7.org/linux/man-pages/man7/rtld-audit.7.html

Do you know where i can find a list of all LD_XXX environment variables?

Read The Fine Manpage

ld.so

The man page ld.so has ENVIRONMENT section that looks pretty good.

Otherwise one of the most reliable options is to simply grep the source code for calls to getenv, I would not be that surprised if their are some extra ones that are undocumented.

Found it - https://man7.org/linux/man-pages/man8/ld.so.8.html#ENVIRONME...

Yeah, i was looking for little known/undocumented environment variables (eg. i didn't know of LD_AUDIT).

A couple of posts on how to use LD_AUDIT;

Leveraging LD_AUDIT to Beat the Traditional Linux Library Preloading Technique - https://www.sentinelone.com/labs/leveraging-ld_audit-to-beat...

rtld-audit and LD_AUDIT - https://vsoch.github.io/2021/ldaudit/

Used this once to debug an issue where it turned out unwanted exports in one library A where used to satisfy imports in another library B and thus preventing library A from being unloaded. Fun times.

The ldd command is also essentially just a wrapper script that sets LD_* variables that get the dynamic loader to do all the real work.