```
Maintain comments on the external interfaces rather than on the internal
functions that implement them.
```
Partial backport of [[https://github.com/bitcoin/bitcoin/pull/22950 | core#22950]]:
https://github.com/bitcoin/bitcoin/pull/22950/commits/29727c2aa1233f7c5b91a17884c405e0aef10c6e
Depends on D12334.