A few examples of issues brought up by Kohl:

- While the PLR explicitly states that “x < y calls x.__lt__(y)”
  [20, §3.3.1.] this is actually false.
  There are cases where x < y does not call x.__lt__(y)
  and there are other cases where x.__lt__(y) is called
  but more than that happens.

- If no expression is provided, the PLR states that
  “the last exception that was active in the current scope”
  should be re-raised. Unfortunately, the PLR stays
  unspecific on what it means for an exception to be
  “the last exception that was active in the current scope.
  [...]
  Instead, raise re-raises the exception that *is active*
  in the respective execution context

(Perhaps unrelated, but indicative of how out of date the PLR is: in executionmodel.rst there's still a mention of and even an index entry for restricted execution, a feature that was removed in some early Python 2 release.)