Question

How does the discrete RF match of the 2.4GHz EFR32 Series 1 PA look?

Answer

The integrated 2.4 GHz PA is a differential PA and there is an on-chip balun as well for the 2.4 GHz part which does the differential to single-ended conversion, but does not do the impedance match to 50 ohms. That is why a simple external (single-ended to single-ended) L-C ladder-structured matching network is required for impedance matching and filtering purposes. The 50-ohm point after the external L-C structure is basically needed for conducted validation capabilities. At the output power level of +10dBm or below the 2-element L-C matching network is recommended, but above +10dBm the 4-element L-C-L-C network is suggested in order to have enough margins at the harmonics.  
Of course, a single-ended antenna can directly be designed at the chip pin which would require to have approx. 20+j10 ohms antenna impedance, but this wouldn't allow having separate tuning possibilities for the conducted spectrum including the harmonic filtering.

More info can be found in the application note AN930.1: https://www.silabs.com/documents/public/application-notes/an930.1-efr32-series-1.pdf