> Please start sentences with capital letters, specifically “mkstemp() and mkdtemp() are lower-level functions . . .”.

This would make the sentence more convoluted... I think that with markup it is pretty clear that this is a function name and the lowercase letter it not misleading.

> The new sentence at the top about context managers seems out-of-place. Perhaps something like “They can also be used as context managers, which triggers the cleanup on exit.”

The two sentences are merged now.

> The new paragraph about cleanup of TemporaryFile is good, but I think it now makes the last sentence of that entry redundant: “. . . can be used in a ‘with’ statement . . .”

Yes, removed.

v3:
- remove sentence “. . . can be used in a ‘with’ statement . . .”
- merge two senteces in first paragraph