The Rest API is fully self-documented through the Rest connection itself (i.e. via a browser).

I don't have it in front of me right now, but I think the simple answer to your question is: No.

As I mentioned in the other thread you just opened, I suggest you open a support Case to see if RWS has any specific suggestions as to what you might be able to do through the Rest API to (at least) determine if XPP licensing is functioning correctly or not.

The RLM license manager is a standalone program that authenticates XPP features through TCP/UDP ports 5053/5054. RLM installs with its own portable web server servlet.

Easiest thing to do is use your browser to check the RLM dashboard.

URL will be:

http://[yourxppserver].[yourdomain]:5054/

Agree with Jonathan, I don't know of a call via the XPPWS API. You might browse the RLM doc to see if they have their own API.

http://www.reprisesoftware.com/RLM_License_Administration.pdf

This was just brought to my attention and may help you in using the REST API to determine if there is a license issue.

It is included near the beginning of the self-documented Rest API (http://REST_hostname:2995/xpp/documentation/index.html).

Look under Utility Functions - Check an XPP license.

It's done with a GET of 

/xpp/license?feature=name

or

/xpp/license

where the default feature checked is "compose".

If you get back a 'false' code along with an error message, it probably indicates that there is a license issue.