Where is the basic Control-TAB (MRU) behavior in Xcode?

Question

In most multi-document editors for windowing environments, Control-TAB will utilize an MRU list to bring the user back to the last visible file. What

Answer 1

In recent XCode (10.3), when in a code editor press:

ctrl+1, right, right

Then use up and down keys and enter to select from the MRU sorted list of recent files.

There is even an option to increase the size of the history.