Docs claim that \r is a possible value for os.linesep, however, I can't find any code that actually sets it to \r.

But it can only be:

• cpython/Lib/os.py

  Lines 52 to 54 in 5334732

  	if 'posix' in _names:
  	name = 'posix'
  	linesep = '\n'

  for POSIX

• cpython/Lib/os.py

  Lines 76 to 78 in 5334732

  	elif 'nt' in _names:
  	name = 'nt'
  	linesep = '\r\n'

  on Windows

Docs:

.. data:: linesep

   The string used to separate (or, rather, terminate) lines on the current
   platform.  This may be a single character, such as ``'\n'`` for POSIX, or
   multiple characters, for example, ``'\r\n'`` for Windows. Do not use
   *os.linesep* as a line terminator when writing files opened in text mode (the
   default); use a single ``'\n'`` instead, on all platforms.

The internet says:

Windows: '\r\n'
Mac (OS 9-): '\r'
Mac (OS 10+): '\n'
Unix/Linux: '\n'

So, it looks like an outdated doc?

Linked PRs

• gh-136087: Remove \r from documented os.linesep values #136088
• [3.14] gh-136087: Remove \r from documented os.linesep values (GH-136088) #136111
• [3.13] gh-136087: Remove \r from documented os.linesep values (GH-136088) #136112