In this folder there is a short.zip
They are 2 keystroke comands like EA for Erase All, EL for Erase Last and ZP for Zoom Previous".
short.txt Here is the program in text format to view direct on-screen. It is includes some general comments.
If you copy this short.txt file by whatever means rather than downloading the zipped files, ensure the copy you put in your AutoCad Support folder has the extension changed to .LSP
Here is a accumulated summary of what I have learned looking at the code and comments.