I’ve only looked at a single study but it said the Mozambique gas was strictly thermogenic. I would expect biogenic gas to have more CO2.
In any case, the Mozambique gas is remarkably clean of problematic accessory gases (CO2 H2S). The only significant non hydrocarbon seems to b N2 at avg about 3%. The N2 is probably helpful for reducing clathrate formation if there’s any water in the stream.