I second the motion for IDLE. There is no module doc for it.

Off the top of my head, there should be a general section that
* says what it is, and that it depends on tcl/tk and tkinter install;
* mentions the existent of the menu Help / IDLE help document;
* gives common startup methods from command line (I forget this) or inside interpreter ('from idlelib import idle') and that one may need to use one of these to see tracebacks if Idle crashes - even if one normally uses a system-specific method to directly run as gui app.
* gives other common info and trouble-shooting tips (some of this is on tracker - such as deleting user .cfg that prevents startup).
* points to system specific discussions, where ever they are put.

Then for each system,
* tcl/tk situation
* how to directly start up
* location of config files

Windows: (what I use)
tcl/tk comes with system.
...

*nix: 
tcl/tk probably already on system
...

mac: (ned daily)
special tcl/tk issues, special page on site
...