If you search in the index, there is no entry like 'append (list method)', only 'append (sequence method)': https://docs.python.org/3/genindex-A.html
This goes to the reference docs, where list methods are documented indirectly by reference to the Sequence protocol described just above the list section: https://docs.python.org/3/library/stdtypes.html#lists

The tutorial page lists all methods for people learning, with noindex markup to avoid pointing from the index to the reference: https://github.com/python/cpython/blob/3.10/Doc/tutorial/datastructures.rst#L19

The individual decisions make sense, but I think the results is not satisfactory: there is no reference to list.append (etc) in the index or the sphinx inventory (only 'list.sort' is there, from the entry in the library/stdtypes list section).  I think index markup should be added for all built-in types in the stdtypes page so that links are generated.  Alternatively, add a sphinx directive to register that a type matches the sequence (etc) protocol, so that index entries for all protocol methods can be generated automatically.