Here's an updated version.

Online: https://www.python.org/dev/peps/pep-0616/
Source: https://raw.githubusercontent.com/python/peps/master/pep-0616.rst

Changes:
    - More complete Python implementation to match what the type checking in the C implementation would be
    - Clarified that returning ``self`` is an optimization
    - Added links to past discussions on Python-Ideas and Python-Dev
    - Specified ability to accept a tuple of strings
    - Shorter abstract section and fewer stdlib examples
    - Mentioned 
    - Typo and formatting fixes

I didn't change the name because it didn't seem like there was a strong consensus for an alternative yet. I liked the suggestions of ``dropprefix`` or ``removeprefix``.

All the best,
Dennis
_______________________________________________

>>> s = 'foobar' * 100 + 'bar'
>>> prefixes = ('bar', 'foo')
>>> while len(s) != len(s := s.cutprefix(prefixes)): pass
>>> s
'bar'

or the more obvious and readable alternative:

>>> s = 'foo' * 100 + 'bar'
>>> prefixes = ('bar', 'foo')
>>> while s.startswith(prefixes): s = s.cutprefix(prefixes)
>>> s
'bar'


Er no, in both these examples s is reduced to an empty string.

Best wishes
Rob Cliffe