SAE.MAF - C.A.R.B. Mandated PID that returns airflow in grams per second. GM (and all manufacturers) are required by law to provide this PID. Also, C.A.R.B. mandated a scaling that is different from the GM.MAF version of this PID. Therefor you will see slightly different values due to different processing required to format each value.
GM.MAF - see above.
GM.DYNAIR - GM's estimated airflow in grams per second based on the VE table. This value is calculated independantly of the MAF. It is used to test MAF rationality and when the PCM is in speed density mode (i.e. MAF removed or disabled).
CALC.CYLAIR - EFILive's calculated grams/cylinder value. It is calculated as {SAE.MAF.gps}*15/{SAE.RPM}
GM.DYNCYLAIR - GM's estimated airflow in grams per cylinder based on the GM.DYNAIR value.
GM.CYLAIR_DMA - internal (DMA) PID that is used by the PCM as an index to look up various tables that are indexed on grams/second. This values is derived from the MAF signal.
GM.DYNCYLAIR_DMA - internal (DMA) PID that is used by the PCM as an index to look up various tables that are indexed on grams/second. This values is derived from the MAP, RPM, IAT and VE tables and is independant of the MAF.
We added the last two (DMA) PIDs because they give more accurate feedback of the indexes (indicies?) used by the PCM when looking up table values. We found that the non-DMA PIDs sometimes lagged actual operating conditions by a frame or two.