In case anyone comes looking at this thread... I just flew SFO-YYZ-DUB, and my YYZ-DUB boarding pass had "ITI OSS" (International-to-International One Stop Security) above the scan block. After deplaning and walking towards connections, there was a lane to the left that was for international transfers. I showed my boarding pass, entered an area where I scanned my passport, got a receipt, then showed my boarding pass again to exit, down an escalator, and I was at the E gates. No customs, and no physical security re-screening. There was no one else using this route in front of or behind me, and total time was less than 2 minutes.