Will only display nonce token if the current user has permissions for unfiltered html. Won't display the token for other users.
The function was backported to 2.0.10 and was added to versions 2.1.3 and above. Does not exist in versions prior to 2.0.10 in the 2.0 branch and in the 2.1 branch, prior to 2.1.3. Technically added in 2.2.0.
Backported to 2.0.10.