even if I don't, I probably need to be able to understand and recognise them when other people do, in libraries/snippets etc that I depend on.

Not specifically a new feature, but I remember wasting a good bit of time when coming across a line that was essentially:

    return headers.get('x-foo') == settings.FOO_KEY is not None

and being extremely confused until discovering it was a use of comparison chaining[1] and was actually doing the right thing.

[1] https://docs.python.org/3.10/reference/expressions.html#comp...