Interesting attempt at having webhooks implementation a bit more standardized. This is indeed needed, currently everyone does them in slightly different ways and sometimes the quality is debatable. If it gets adopted it'd give a good baseline.

An interesting interpretation of what was behind the "move fast and break things" motto which is nowadays blindly followed by some. A bit of a long piece but does the job and propose a more complete view and an alternative approach.

The fact that they felt the need to write such a letter is troubling. What's going on in the Python Software Foundation really? Something needs to be fixed it seems.

Definitely this. Again TDD helps to work on the design, but it's not a silver bullet which will give you the right design on a platter.