With 5.6 release, we have rewritten many of the REST docs.
At least parts of them should be backported to DOCS55, 54

• REST security
• REST API and all the children pages (besides delivery)

But: Don't do it, as long as "Getting stared with REST (@DOCS56) has not been "improved"
And problem: ""Getting stared with REST" may need adaptions to reflect REST 1.x (DOCS56 has REST 2.0).
To be discussed with the team ...