I want to build up my own desktop environment (like an Openbox/i3 setup) from a base. I don't want any pre-existing DE since I want to learn about all the components required to make a running DE on my own. Now the only "flavour" that Ubuntu offers in this respect is "Ubuntu Server". Now, my question is whether the Ubuntu Server ISO comes with any server-oriented stuff preinstalled. As far as I understand it is supposed to be very bare, but the website isn't very verbose about what comes preinstalled. So does it have anything like Apache, Docker, network-management tools etc preinstalled that I'd have to remove? Also, could someone point me to where the preinstalled packages are listed?

Edit:
Version which I am interested in is 20.04, the current LTS release. Also, the "minimal" install offered is standard Ubuntu with the DE, just stripped down to very small number of apps such as a web browser. That is not what I want. I want no preinstalled DE. I am fine with installing stuff from the Server ISO, I just need to know if there are really "server" stuff that I'd have no need for. Unless I know they exist and what they are, I can't remove them. Hence the question.