query_cache_type default was changed from ON to OFF with MariaDB 10.1 GA, and it is OFF when installing from source, from a binary tarball, or from RPM packages on RHEL/CentOS

Query cache is ending up still being enabled on Ubuntu (and probably Debian, too), all the way to MariaDB 10.4, as there the distributed my.cnf contains

{{query_cache_size = 64M}}

As this setting is different from the compiled in default of 1M, this automatically sets query_cache_type to ON, too, as documented:

Starting from MariaDB 10.1.7, query_cache_type is automatically set to ON if the server is started with the query_cache_size set to a non-zero (and non-default) value.

https://mariadb.com/kb/en/server-system-variables/#query_cache_type

Given that having the query cache enabled usually is doing more harm than good, we should make sure to have it disabled on all platforms by default:

Suggested fix: at least comment out all query_cache_...=... lines in all distributed config files, or remove them completely