Logging

Running Slackware-14.2/x86_64 and postgresql-11.5.

In /var/log/ are these files:

-rw-r----- 1 postgres wheel 0 Nov 23 04:40 postgresql-11
-rw-r----- 1 postgres wheel 723 Nov 23 04:40 postgresql-11.1
-rw-r----- 1 postgres wheel 324 Nov 20 04:40 postgresql-11.2.gz
-rw-r----- 1 postgres wheel 320 Nov 17 04:40 postgresql-11.3.gz
-rw-r----- 1 postgres wheel 322 Nov 14 04:40 postgresql-11.4.gz
-rw-r----- 1 postgres wheel 321 Nov 10 04:40 postgresql-11.5.gz
-rw-r----- 1 postgres wheel 325 Nov 6 04:40 postgresql-11.6.gz
-rw-r----- 1 postgres wheel 337 Oct 23 04:40 postgresql-11.7.gz

I assume that they're an automatic backup that runs every 3-4 days. What's
backed up and where is this controlled?

I ask because I have a cron job that does a pg_dumpall each night at 11:30
pm. (It's a small installation for my business use so the files are not
excessive and I keep them for only short periods.)

Regards,

Rich