results.webkit.org API should include commit identifier information in test results data. Currently it doesn't. For e.g.: https://results.webkit.org/api/results/api-tests/TestWebKitAPI.IndexedDB.DatabaseProcessKill?platform=ios&style=release returns lot of results, but each result data is like this: {"actual":"PASS","expected":"PASS","start_time":1610587496,"uuid":161057193600}. It doesn't indicate which commit identifier does that result corresponds to. Such information should be included.
The uuid is the abbreviated commit representation, if you already have a commit (with timestamp) you can find the uuid for that commit, or uuids which are near your commit. For EWS, though, adding `before_ref=<hash/revision/identifier>` to the query to the REST API is probably the quickest way to get what you're looking for.
<rdar://problem/76845849>