Thanks! I was looking for that.

I see they use those cheapo Chinese RF modules (SA818). I've seen those also with SDR input/output, that's interesting. The underlying chip is very similar: The chip that will be used in this module is the RDA1846. This is a chip that's in most Chinese handhelds and is internally fully SDR but it decodes to analog. There's also the RDA1847 with similar pinout which offers the raw SDR stream and can thus be used for any mode, but with the added complexity of having to do the SDR decoding externally.

That means that this design could probably also be modified to do DMR. Though the SDR side might be a little bit too much to ask of an ESP32. On the other hand, it is only a very low bitrate signal.