This is a fair comment, Sri; I do agree with you -
I’ve reviewed the Service Development Help guide and I see that the REST content has been gradually reduced from 10.5 through 10.11. For instance, content on the legacy approach is no longer available in 10.11, which is fair in my opinion. The part that I see missing is about how the IS handles REST.
I’m positive that there was some thought process to why this was moved and slowly trimmed; I will ask around and get back 
I’d suggest that you create a support ticket to get a quicker/formal response.
KM
#webMethods#Integration-Server-and-ESB#Flow-and-Java-services