As I wrote somewhere, I did it using the “restore factory” from the File menu. I remembered that from when I started with Blender more than a decade ago. Nope, I’m not a veteran, I never went further than rendering a cube, LOL.
But as everybody has found out how to do it easily, here is how to do it like a real 1337 H4KZ0R !! (PH34R M4H SK1LLZ)
Open a terminal or some other way and search for the file startup.blend
It’s in the .blender directory somewhere in the filesystem.
OK, I’ll tell you where it is:
Linux: ~/.blender/VERSION/config
Mac: ~/Library/Application Support/Blender/‘Version Number’/config/startup.blend
Win: C:\Users$user\AppData\Roaming\Blender Foundation\Blender’Version Number’\config\startup.blend
Delete this file, restart Blender, done.