These (and a few others that can be revisited later if needed) were present in
beta versions of the WP REST API but were removed during the merge to WP 4.7.
Props ChopinBach, jnylen0.
Fixes#38693.
git-svn-id: https://develop.svn.wordpress.org/trunk@40605 602fd350-edb4-49c9-b593-d223f7449a82