How to disconnect selected mesh geometry? I don't know how to disconnect a face from the rest of the mesh in edit mode.

This isn't like pressing P to separate the selection into a completely different object. I just want to select a face and disconnect/rip it away from the rest of the mesh but keep it as a part of the original object.

One way to do it would be to duplicate the face with ShiftD and then delete the original face. But I suspect there is a "native" command for disconnecting selected faces and I would like to learn it.
The command I am looking for is "split" and you can select it with Mesh > Vertices > Split, menu or by pressing the keyboard shortcut Y.