{
  "schema": "perfowl.startup-mach-clock-bridge-validation/1",
  "date": "2026-09-06",
  "privacy": "anonymous",
  "activityTraceConcurrency": [
    {
      "caseAlias": "ios17-single-owner",
      "osMajor": 17,
      "dtxProviderCount": 1,
      "activityTraceSelectedRows": 2,
      "coreProfileDecodedRecords": 0,
      "droppedEventHighWater": 0,
      "result": "trace-session-conflict"
    },
    {
      "caseAlias": "ios17-dual-owner",
      "osMajor": 17,
      "dtxProviderCount": 2,
      "activityTraceSelectedRows": 1,
      "coreProfileDecodedRecords": 0,
      "droppedEventHighWater": 0,
      "result": "trace-session-conflict"
    },
    {
      "caseAlias": "ios18-single-owner",
      "osMajor": 18,
      "dtxProviderCount": 1,
      "activityTraceSelectedRows": 12,
      "coreProfileDecodedRecords": 0,
      "droppedEventHighWater": 0,
      "result": "trace-session-conflict"
    }
  ],
  "coreProfileControls": [
    {
      "caseAlias": "ios17-coreprofile-only",
      "osMajor": 17,
      "coreProfileDecodedRecords": 401517,
      "identityStatus": "verified",
      "droppedEventHighWater": 0,
      "result": "source-observed"
    },
    {
      "caseAlias": "ios18-prior-semantic-batch",
      "osMajor": 18,
      "coreProfileSessionCount": 9,
      "coreProfileDecodedRecords": 5645809,
      "identityVerifiedSessionCount": 9,
      "dropZeroSessionCount": 9,
      "result": "source-observed"
    }
  ],
  "decision": {
    "activityTraceInRealtimeStartupChain": false,
    "secondDtxOwnerAdded": false,
    "replacement": "fixture-mach-absolute-offline-bridge",
    "reason": "ActivityTrace and CoreProfile did not concurrently produce CoreProfile records on either one or two providers."
  },
  "implementationEvidence": {
    "pythonTests": 164,
    "swiftTests": 80,
    "fixtureUnsignedBuild": "passed",
    "siteBuild": "passed",
    "fixtureSignedBuild": "blocked-external-provisioning-update-not-approved",
    "ios17MarkerBridge": "not-tested",
    "ios18MarkerBridge": "not-tested"
  }
}