The proposed patch does several things that can be considered independently.

1. Give the 'title' parameter a default value 'About IDLE'.  Instead, add the python/IDLE version, as done for IDLE doc in help.py.  (In both cases, one might wonder why title is a parameter rather than being calculated within __init__.  Perhaps an example of YAGNI.)

2. Make About IDLE non-modal.  The addition of show(), _destroyed(), and changes in AboutDialog.close() are part of this.  Modal seems standard, at least on Windows.  What about other systems?

Mozilla FireFox and Thunderbird are obnoxiously semi-modal.  Steam launcher is fully modal, with an icon added to the Taskbar, so one can easily find the window to close it.  Any patch must make sure this happens. Clicking About Steam menu entry a second time lifts the first window to view.  The patch imitates this.

To me, the main justification to go non-modal is that About IDLE opens documents in custom read-only windows rather than in a browser.  README is one that one might want to keep open for awhile.  Ditto for a future Roadmap file.

3. Add an icon with code based on the commented out code we removed (see lines with 'logofn', self.picture, and labelPicture).  Yes, but we should try using the better looking "idle_48.png" with tk 8.6.

4. Change from white on medium gray to black on light gray.  I might also try the standard black on white.  Or black on python yellow.  If we do A. below, the background should work with the blue link tagging.

5. I believe all 6 of the current linked documents are pre-loaded.  I think this unnecessary as they are generally ignored.  Load on demand is fine.

6. Documents are displayed in a new read-only Text that is part of the dialog itself.  If we went in this direction, I would want to first try using the new TextviewFrame.  But I think it better to open textviews non-modally so one can keep a document around after closing AboutIDLE.  I think this will be more true if/when we switch to tabbed notebooks or the equivalent.

A. What the patch does not do is switch from buttons to blue-underlined links, as I have discussed elsewhere, nor do other rearrangements and changes.  I want to move What's New to the top, move the Python license and copyright to the bottom, and remove Python credits.  The idle-dev email must be replaced with a link to the idle-dev subscription page, as spam (which continues) prompted a switch to subscription required.  This will be a separate issue.