Dealing with annotations is complicated.  I think there should be a section of the Python documentation describing best practices for working
with annotations.  So, here goes.

The best spot I found for it was as a new HOWTO.  I added links to that HOWTO to a couple relevant glossary definitions, and one in the documentation for inspect.get_annotations().  I'm not sure if it makes sense to add any other links; I considered adding links to the HOWTO to where the __annotations__ attribute is defined on functions, modules, and classes, in reference/datamodel.rst, but it just didn't seem like a good idea.