Currently registered issues:

1) Atomic Grouping / Possessive Qualifiers

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-01

2) Named Match Groups as Match Attributes

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-02

3) Match objects support Array Indexing

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-03

4) Add support for Perl-Style Relative Back References

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-04

5) Allow Parenthetically Well-Nested Comments in Regular Expressions

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-05

6) Add support for fixed-width Expression matching, enabling the undocumented Template option

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-06

7) Better compiled expression Cache

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-07

8) Emacs / Perl like Named Character Sets

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-08

9) Engine Cleanups, Documentation and general Improvements

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-09

9-1) New Engine Proposal that replaces pseudo-recursion with a Single Loop

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-09-01

9-1-1) New Engine Proposal that replaces pseudo-recursion with Three Nested Loops

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-09-01-01

9-2) New Engine designed by Matthew Barnett

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-09-02

9-3) New Engine based on Thompson Non-Finite Automaton (NFA)

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-09-03
    [ http://bugs.python.org/issue1662581 ]
    [ http://bugs.python.org/issue1721518 ]
    [ http://swtch.com/~rsc/regexp/regexp1.html ]

10) Reduce use of Magic Numbers by sharing Constants between the C-Engine and Python

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-10

11) Catch-All for any other Perl 5.10.0 / 6.0 features we may wish to add

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-11

12) Clarify elements of the Documentation about how Regular Expression Comment nesting works

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-12

13) Add a grouptuple method to the Match object which would return a 3-tuple for each match group

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-13

14) Allow UNICODE Match Group Identifiers

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-14

15) Add __doc__ strings to the Pattern_Type, Match_Type and Scanner_Type classes

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-15

16) Implement various FIXMEs

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-16

16-1) Allow the deletion of the string attribute associated with a Match object

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-16-01

17) Variable-Length Positive and Negative Look-Behind Expressions

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-17

18) Allow for Strings to be scanned in Reverse by a given Regular Expression Pattern

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-18

19) Allow In-Line Pattern Flags to be Positionally Dependant

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-19

20) Allow In-Line Pattern Flags to be Negated

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-20

21) Allow Scoped In-Line Pattern Flags

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-21

22) Change how a Zero-Width Pattern splits a string

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-22

23) Fix inconsistencies in how Character Ranges work in Case-Insensitive Character Classes

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-23

24) Fix missing character bug in findall / finditer methods

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-24

25) Allow sub-expressions of size greater than 65535

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-25

26) Allow Capture Groups in Look-Behind expressions

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-26

27) Allow UNICODE (\u, \U) escape sequences in Regular Expressions

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-27
    [ http://bugs.python.org/issue3665 ]
    [ http://bugs.python.org/file11235/re_unicode_escapes.diff - Georg Brandl]

28) Add Flags parameter to re.split, re.sub and re.subn

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-28
    [ http://bugs.python.org/issue3482 ]
    [ http://bugs.python.org/issue3255 ]

29) re.sub / re.subn should allow Unmatched Group replacement via empty string

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-29
    [ http://bugs.python.org/issue1519638 ]

30) re.escape should only escape non-alphanumeric characters that are known Regular Expression operators

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-30
    [ http://bugs.python.org/issue2650 ]
    [ http://bugs.python.org/file10080/re.patch (Russ Cox) ]
    [ http://bugs.python.org/file10084/re.patch (Russ Cox) ]
    [ http://bugs.python.org/file10130/re.patch (Lorenz Quack - add Frozen Set to store characters) ]
    [ http://bugs.python.org/file10215/re_patch.diff (Rafael Zanella -- combo w/ dict) ]

31) Make sure \w properly matches non-Roman scripts
    a) Verify Regexp2.7 uses UNICODE 5.x
    b) Verify whether Mc, Mn and Me character classes should be classified as Spaces or Words

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-31
    [ http://bugs.python.org/issue1693050 ]

32) Add support for immutable bytes and mutable buffer objects in the place of basestring types

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-33
    [ http://bugs.python.org/issue1282 ]
    [ http://bugs.python.org/issue1708652 ]
    [ http://www.python.org/dev/peps/pep-3137 ]

33) Ignore redundant repeat operators (e.g. in '(x*)*', '(x*)?', '(x*){n}' and '(x*){n,m}')

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-32
    [ http://bugs.python.org/issue2537 ]
    [ http://bugs.python.org/issue1633953 ]
    [ http://bugs.python.org/issue1456280 ]
    [ http://bugs.python.org/issue214033 - (x?)? - No longer pertinent ]

34) Add support for exact (start to finish) matches via an exact method on the pattern object (e.g. exact == search(r'\A...\Z', ...) == match(r'...\Z', ...))

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-34
    [ http://bugs.python.org/issue1708652 ]

35) Add support for PCRE-style Regular Expression subroutines

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-35
    [ http://bugs.python.org/issue694374 ]
    [ http://manpages.courier-mta.org/htmlman3/pcresyntax.3.html ]

36) Add option to make \Z and \z operate like Perl / the PCRE, e.g. re.PERL, re.E, (?E)

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-36
    [ Suggestion by Matthew Barnett ]

99) Solve the mysterious PyObjectDel / Py_DECREF debug memory issue

    https://www.launchpad.net/~pythonregexp2.7/python/issue2636-99
    [ http://bugs.python.org/issue3299 ]
    [ http://bugs.python.org/file10891/_sre-2.patch (Victor Stinner) ]
    [ http://bugs.python.org/file10892/_curses_panel.patch (Victor Stinner) ]
    [ http://bugs.python.org/file10893/pyobject_del.patch (Victor Stinner) ]

A number of these issues have combined solutions as well as the core solutions listed here; see https://code.launchpad.net/~pythonregexp2.7 for a complete list of all current branches.

This is a group engaged in updating the current Regular Expression engine in the Python programming language to support enhanced features, various bug fixes and better documentation.