We previously learnt to measure the use of SERVICE syntax in queries running on Wikidata Query Service, but we know that this data includes both successful and failed attempts to federate.

This task is to find a way to recognize whether the use of SERVICE syntax resulted in a successful or failed outgoing subquery.

Keep in mind that we should not pay attention to the use of this syntax to invoke helpers - T399827.

We start with a timeboxed investigation of the feasibility and depending on the outcome, make a decision whether to proceed with the actual implementation in the data.