I would like to develop and endpoint to support callouts from AMP page as defined in https://github.com/ampproject/amphtml/blob/master/extensions/amp-a4a/0.1/callout-vendors.js
Describe the new feature or change to an existing feature you'd like to see
There is plenty of information about how to implement header-bidding with FastFetch and RTC config from a publisher's perspective. However, it seems pretty hard to find the appropriate documentation for vendors who want to register as compliant in callout-vendors.js
Describe alternatives you've considered
Can't we add any "Getting Started" documentation for such cases?
Additional context
It seems that a vendor simply has to register in https://github.com/ampproject/amphtml/blob/master/extensions/amp-a4a/0.1/callout-vendors.js (as well as rtc-documentation.md and rtc-publisher-implementation-guide.md) Is that correct?
The integration requires the vendor to set up an endpoint that will be able to receive a GET HTTP request and parse the information that he can define through MACROS or directly from the attributes that are defined in the tag (e.g: &w=ATTR(width)&h=ATTR(height)) Is that correct?
What about errorReportingUrl and disableKeyAppend?
A proper page for the vendors would be great! Thanks :)
