> All .py files should be converted.

I disagree. For example, people decided that all .py files in Tools
should get converted, converting Tools/msi in the process. Now,
Tools/msi is intended to be run in an *older* Python version than the
one being packaged; I currently use 2.4 to do the packaging. It took me
some time to undo this conversion.

It's convenient if users can easily express which files they want to
convert, but it must be a selective, explicit choice.

> I can't think why a project would
> use this 2to3 capability for scripts and packages, but not .py files in
> data files.

See above.

> Would the motivation become clearer if we modified
> Demo/distutils/test2to3 to install a README.txt and a demo .py file
> (where the demo .py file should not be installed in the global 'scripts'
> directory, but instead in a 'demos' sub-directory of the package)?

I understand the motivation fully (I think). I just question whether it
is general. Packages that have this need (to 2to3-convert data files)
would have to come up with their own command subclass still, which
hopefully is very easy with what we provide.

IMO, this is a case where we should err on the conservative side. If we
don't provide the command in 3.0, people will write their own. If your
assumption is correct that this is a common need, we can still add the
command into 3.1.