Player Experience Upgrade
version 2/111127 by Aaron Reed
The extension is known to be compatible with Locksmith by Emily Short, Keyword Interface by Aaron Reed, and probably many others.
The extension will technically compile as z8, but you may not be able to squeeze a very large game in with it. I highly recommend switching to Glulx.
This extension should NOT be used with any of its component extensions: they are duplicated entirely within it. It should also not be used with Default Messages by David Fisher, which was the go-to extension for replacing library messages up until about mid-2010, nor with extensions offering partially overlapping functionality, such as alternative methods of processing implicit actions.