Try this code:
const walker = document.createTreeWalker(document.body);
let x = walker.lastChild();
Now hover over the token "lastChild". I expected the summary comment to be a complete valid sentence, like this (copied from MDN):
The TreeWalker.lastChild() method moves the current Node to the last visible child of the current node, and returns the found child.
Instead, the hover highlight is an invalid incomplete sentence:
The TreeWalker.lastChild() method moves the current the found child.
I'm not sure how this happened specifically for this API - as the other API summaries looked correct. I'm not sure which other DOM APIs are affected.