No, not "prepdf-polynomial". I just checked 23R1 and I could see "laminar-flame-speed-computed" (see screenshot below). It's also described in the Theory Guide:
8.3.2. Partially Premixed Combustion Theory
It's not clear why you are not getting the option. Could you send a screenshot of the "Chemistry" tab of the "Species Model" dialog box? Also please double check the release numer?
You are navigating away from the AIS Discovery experience