We need to mention somewhere reasonable that you need to create a config folder in your zip version of blender to make it self-contained.
The zip version should include the config folder by default. (which might cause more problems if people try to manually install that into their program files or somewhere else and forget to remove the config folder)
Why is this a problem? The general impression is that the zip version is portable out of the box, when it's not. And the way to make it portable isn't documented anywhere.
I discovered that the zip version of blender is not actually portable by default. I've had the impression for years that the installed version is non portable and the zip version is portable.
I know now that you need to create a config folder inside your blender install directory and then blender will put it's addons, default start up file, config data etc in there... making it portable.
But this doesn't appear to be documented anywhere official, just on the occasional forum.
The real problem is that the general information out there gives the impression that the zip file is portable, when it's not... not by default. It's true that it will run from a flash drive and that it doesn't require administration permissions to save configuration data, but it will put those config files on the computer, rather than the flash drive.
How many hours has this cost me in total of being slightly confused about what's going on? About 4... and counting (including creating this report).
I think put a link here called "Make Portable, or Make Self-Contained, or Portable Installations" which will go to a new page that mentions to put the config folder inside the install directory to make blender portable.
My personal preference would be to make the zip install portable by default though. Or to even offer a separate download to a "portable zip version" if making the zip version truly portable by default is an issue.