issue2636-features-5.diff includes:

Bugfixes
Added \G anchor (from Perl).

\G is the anchor at the start of a search, so re.search(r'\G(\w)') is
the same as re.match(r'(\w)').

re.findall normally performs a series of searches, each starting where
the previous one finished, but if the pattern starts with \G then it's
like a series of matches:

>>> re.findall(r'\w', 'abc def')
['a', 'b', 'c', 'd', 'e', 'f']
>>> re.findall(r'\G\w', 'abc def')
['a', 'b', 'c']

Notice how it failed to match at the space, so no more results.