https://docs.python.org/3/reference/expressions.html#comparisons claims that "Comparisons yield boolean values: True or False." But that's not necessarily true:

```python
>>> class Spam: 
...  def __eq__(self, _): return 42
... 
>>> Spam() == object()
42
```

That really only happens when an expressions is used in a boolean context like an `if` statements guard expression.

For rich comparisons, a proper explanation is given in the rich comparison entry in the datamodel section ( #41910) 

"A rich comparison method may return the singleton NotImplemented if it does not implement the operation for a given pair of arguments. By convention, False and True are returned for a successful comparison. However, these methods can return any value, so if the comparison operator is used in a Boolean context (e.g., in the condition of an if statement), Python will call bool() on the value to determine if the result is true or false."

bool(x) calls x.__bool__ and requires that the latter return False or True.

As for the other two comparisons, x is y always returns False or True for a proper implementation because int == int always does.  If y.__contains__(x) does not raise, x in y returns bool(y.__contains__(x)), clamping aberrant implementations of __contains__.

A replacement text might be 

"Comparisons normally yield boolean values: True or False.  But rich comparisons not in a Boolean context may yield anything."

Possibly link 'rich comparisons' to the datamodel section.

It turns out the "expressions" page of the language reference makes multiple claims about types which do not hold, e.g. for multiplication, "The arguments must either both be numbers, or one argument must be an integer and the other must be a sequence", or for `&` that its arguments "must be integers".

So this is much larger than just comparison operators.

I've put up a PR here: https://github.com/python/cpython/pull/27470/files

New changeset 4bd9caafb64589288e5171087070bde726178c58 by andrei kulakov in branch 'main':
bpo-41911: Update docs for various expressions (GH-27470)
https://github.com/python/cpython/commit/4bd9caafb64589288e5171087070bde726178c58

New changeset 843b3d28209b7754c51c6cc3844f66808b6dbdaf by Miss Islington (bot) in branch '3.10':
bpo-41911: Update docs for various expressions (GH-27470) (GH-27490)
https://github.com/python/cpython/commit/843b3d28209b7754c51c6cc3844f66808b6dbdaf

New changeset b57011d2a5375bc9f255361dc64c9e6fbc203e0e by Miss Islington (bot) in branch '3.9':
bpo-41911: Update docs for various expressions (GH-27470) (GH-27491)
https://github.com/python/cpython/commit/b57011d2a5375bc9f255361dc64c9e6fbc203e0e