Those engines likely have an extra little "nub" on the camshaft that pops the exhaust valve open a small amount for a short time just before TDC, relieving some cylinder pressure.
This is effective at cranking speed, still happens "at speed", but not enough time to have much effect, so it doesn't need to be "shut off" after starting, as Kohler did with the centrifugal ACR on the old K-series engines.
Throttle lever/choke has NO effect on the compression release function on your Briggses.
