Is tmpfiles.d deleting my core files?

I'm investigating why my core dump files are being deleted on every reboot. I checked the /etc/tmpfiles.d/ directory and it is empty. I checked /usr/lib/tmpfiles.d/systemd.conf and found: # Handle lost systemd-coredump temp files. They could be lost on old filesystems, # for example, after hard reboot. x /var/lib/systemd/coredump/.#core*.%b* r! /var/lib/systemd/coredump/.#* I'm trying to understand the man file, but it looks like the first line says exclude the /var/lib/systemd/coredump/XXX directory altogether. (I don't understand the .#core.\*.%b* syntax). And the second line says remove empty directories at /var/lib/systemd/coredump/XXX and recurse. (Again, the suffix I can't explain). Would either of these two lines be deleting my coredump files on every reboot? Would I solve the problem by copying the systemd.conf file to /etc/tmpdilfes.d/coredump.conf and change as follows: x /var/lib/systemd/coredump/.#core*.%b* 0755 root root 20d r! /var/lib/systemd/coredump/.#* 0755 root root 20d