It would be good to have access to more page-wide metadata so the Mobile-Content-Service doesn't have to make extra mobileview/ MW API requests, in order of importance:
The only other piece of info Parsoid fetches that we could add is page id and whether it is the main page.
protection, languagecount is not provided in the revisions endpoint and we would have to make additional API calls to add them. As for thumbnail image URL, what is that, as in, is that something the API provides or is that some inferred / heuristic value set by looking at the page output?
Change 307880 had a related patch set uploaded (by Subramanya Sastry):
WIP: T119265: Add more page-level metadata required by MCS
The thumbnail image URL is the information about the lead image for the page. It's provided by the mobileview action.
If you don't get all the values I'd say it's probably not worth for Parsoid to make additional calls. Similarly for MCS, we may not want to change what we're doing if we still need to make additional requests.
Change 307880 merged by jenkins-bot:
T119265: Add more page-level metadata that MCS can use
Mentioned in SAL (#wikimedia-operations) [2016-12-14T21:27:00Z] <arlolra> Parsoid updated to version 60ee19ac (T119265, T104523, T104662)
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Based on this, I am going to close this ticket. Please reopen / create a fresh ticket, if anything changes here.