What data belongs in api_url vs. api_data_url?

Working on fetchcode/package.py and related files for the `metadata` command output data, including adding cocoapods download support, I have used the `api_url` key for one of the three cocoapods podspec URLs:

- `f"https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/{hashed_path}/{name}/{tag}/{name}.podspec.json"`

Some (many?) PURLs with a GitHub repo define their `api_url` key using the `"https://api.github.com/repos"` path which leads to JSON data, e.g.,

- pkg:github/avahi/avahi@0.8 -- "api_url": "https://api.github.com/repos/avahi/avahi"

Most cocoapods seem to have a GitHub repo, and thus my use of `api_url` for cocoapods podspec files prevents using that key for the `"https://api.github.com/repos"` JSON data (if available). The only other URL key I see that perhaps could be used by cocoapods PURLs is `api_data_url`. I don't recall seeing any info() output where `api_data_url` had a value, but maybe I missed it.

An example of a cocoapod with a podspec URL and a `"https://api.github.com/repos"` JSON file:

- `pkg:cocoapods/ZendeskSDK@4.0.1`
- https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/6/5/9/ZendeskSDK/4.0.1/ZendeskSDK.podspec.json
- https://api.github.com/repos/zendesk/zendesk_sdk_ios

Is there a preferred set of keys to use for cocoapods that have both a podspec URL and a GitHub repo (and thus might also have `"https://api.github.com/repos"` data)?