Why the list creates in two different ways? Does it cause by the mutability of its elements? Where the Python document explains it?

[Dieter Maurer]

Chris Angelico wrote at 2021-6-16 02:20 +1000:
>On Wed, Jun 16, 2021 at 2:18 AM Dieter Maurer <dieter at handshake.de> wrote:
>> As far as I know, there are no guarantees are the language level.
>> There are some (partially documented) implementation details
>> for CPython (which is just one possible implementation).
>
>Yes there are - plenty of them :) The example I gave is a language
>guarantee.

Would you point to the documentation location where this is guaranteed?

--
Dieter