Discovery
List the request-template variables
The placeholders a request template (url / query / headers / body of any api stage) may reference, with a one-line description, an example rendered value and the stages each one is valid in.
This is the same vocabulary the publish pipeline validates against, so editors and coding assistants can offer exactly what the platform accepts instead of copying a variable list that drifts. Anonymous, like the manifest schema: a deployment-level constant with no caller data.