Tridion's uses tcdl as a "technology-neutral" (markup) language to manage Content Delivery features such as:
See Reference for Server Controls Custom Tags and TCDL tags (requires login).
I understand this means we can request DCPs using .NET, Java, or the CD Web service and get things like DCPs and dynamic links correctly resolved at request time.
We've had a few questions and comments related to
REL (see 1 and 2). I think the general question would be:
Does the syntax or format matter for REL when Content Delivery returns its response? Can REL handle XML (or even text) based DCPs?
I'd guess that over the CD Web Service, the format doesn't matter but .NET requires ASCX and Java needs JSP (as set in a Template's Output Format)?