+2to3 (2.x to 3.0 conversion tool)
+    the 2to3 conversion tool and `Lib/lib2to3/`_
Hm, given that the tool (IOW the script) is only a few lines, I find the line a bit strange; 2to3 == Lib/lib2to3.  (See also below before you reply to that.)

Personal style thing: I don’t like putting os.sep at the end of directory paths.

+    the benchmarks in the `benchmarks`_ repo
reST protip: For sequences of characters without spaces, you can use just benchmarks_.

+Demos and Tools
+    the scripts in `Tools/`_ and `Tools/demo/`_
The files in* (they are not all scripts).  Sidenote: I think English typography would have us capitalize the definition lines.

+Devguide
+    the `devguide`_
The `Developer’s Guide`_

+Distutils
+    the distutil package in `Lib/distutils/`_
Typo: distutils*.

+Distutils2
+    the packaging package in `Lib/packaging/`_
I always call it “the packaging module”, to avoid the weird-sounding, potentially confusing “packaging package”.

+Documentation
+    the documentation in `Doc/`_
Maybe also mention that it’s the source for what’s published at docs.python.org

+Extension Modules
+    C modules in `Modules/`_
I believe some of them are under Lib.  I also don’t know whether imp for example should be Core or Extension Modules.

+IO
+    the IO, `Lib/io.py`_ and `Modules/_io/`_
Maybe “the I/O system”

+Macintosh
+    the Macintosh operating system
That’s vague.  What about “Used for bugs specific to Mac OS X”?

+Regular Expressions
+    regular expressions, and the `Lib/re.py`_ and `Modules/_sre.c`_ modules
Here again, I’m a bit startled by “and”: regular expressions == re.py and _sre.c

+Tests
+    the tests in `Lib/test/`_, the unittest and doctest frameworks in
+    `Lib/unittest/`_, `Lib/doctest.py`_

To make people able to answer “Is this Library or Tests?”, I think we could say something like this: Issues and improvements for tests and test frameworks (unittest, doctest, regrtest).

I’m not sure putting emphasis on the paths, like your patch does, is enough to explain for example the difference between Library and Extension Modules.  If I understand the components correctly, their main utility is to let people be auto-assigned/nosied, or to let people find things that interest them or that they can help with, so for example “Mac-only bug” vs. “universal bug” is a useful distinction, “Documentation” lets people with reST skill find things to work on, “written in Python” vs. “written in C” is also useful, etc.

If the above analysis seems good, then I propose to update your patch, to be fair, as you put time to do this and now I’m basically saying that no line is good :)