I have a question about the last blob in mymining.submit JSON's right after the Nonce (i.e. the "09b66000")

   "3782626",                                // Job ID
    "ec100000000000",                         // Extranonce2
    "67c28154",                               // Time
    "16384721",                               // Nonce
    "09b66000"                                // Extra nonce (optional, rarely used)
  ],
  "id": 19,                                   // Request ID
  "method": "mining.submit"                   // Method name
}

Is there any chance the the S19 ASIC would ever involve this in the hashing process for any reason at all, and if so, how would it incorporate it? I cannot reconstruct a block header with a decent hash value no matter what I try, so now I'm grasping at straws, wondering if this extra field is somehow used. The pool was cruxpool, in case that matters.
-gt-