Someone needs to adjust the "Gus the Cookie" tutor

Support Basics & Interface
1

… to reflect the changes in the new Blender interface.

For example, the key-sequence S X no longer works to flip the two halves (say of the armature) around the desired axis. The key now is Mirror, but our student won’t have a clue.

2

I’m expecting that the new blender manual will have an updated Gus tut.