While I was working on a patch to port wrapt to limited API and stable ABI, I noticed a possible regression in __annotations__ PyGetSetDef. It looks like C heap type subclasses no longer inherit the __annotations__ descriptor from a C heap type parent class. A gdb session confirmed that 3.10 no longer calls the WraptObjectProxy_set_annotations setter of the parent class while 3.9 does.

I had to add 

    { "__annotations__",    (getter)WraptObjectProxy_get_annotations,
                            (setter)WraptObjectProxy_set_annotations, 0},

to PyGetSetDef of the child class in order to fix the behavior. Python 3.9 and older work as expected.

You can reproduce the behavior by disabling WRAPT_ANNOTATIONS_GETSET_WORKAROUND and run "tox -e py310-install-extensions". The PR is https://github.com/GrahamDumpleton/wrapt/pull/187.