Brett, you misunderstood somethings. I want to apply now to 3.3 and 3.4. This is the right time now that 3.2 final maintenance is out. (In any case, we are no longer patching it. 2.7 gets improvements on a 'reasonable best effort' basis.) It is also clearer and can be easily 'translated' into the skeleton of a testcase.

Roger, ditto. But the intent is clear to me.

On my Windows, trying to load 'sys' does bring up the 'source' message box, but without 'return', it next triggers the 'loader' message. A bad name gets all three boxes. Anyway, another example of why to test on more than one OS (assuming you did not use Windows).

Another change: I think "not a source-based module" should be 'not a Python-coded module'. The intent of the feature is to open any python-coded module that can be imported. C-coded modules are also, ultimately, source-based.