I was banging my head not being able to install mariadb and python3-pip in a minimal install of Ubuntu 18.04. Every web search showed pages with the expected apt install package commands. When I installed a desktop version, I see sources.list under /etc/apt has far more lines with desktop than minimal.
Why would these be different for apt sources? I did plain vanilla choices on both.
-rw-rw-r-- 1 root root 2904 Aug 3 15:46 sources.list
-rw-r--r-- 1 root root 164 Aug 1 21:13 sources.list -rw-r--r-- 1 root root 168 Jul 25 23:04 sources.list.curtin.old
I can't post examples since I don't have enough reputation points due to links.