I expect not for existing profiles in case it conflicts with something you have setup already. It probably should for new profiles but I don’t know if it does or not and would likely depend on your linux distribution.
You can easily add it by navigating to the folder, right clicking it and selecting “add to places”.
No, the default set of items in the Places panel hasn’t changed.
Is that intentional?
Yeah. The default contents of the places panel are manually curated; nothing gets added there automatically.
Why do you ask?
I guess it’s about how at first glance the Places panel has a big overlap with XDG user folders, so you could assume both are linked together. Anyway the overlap stops at showing Wastebin and not showing Public, Templates and now Projects.
To know if I would need to file a bug/wishlist like I did for the icon for the same folder.