They used freely available NASA data to map Russian and Ukrainian electronic warfare systems. The jammers used leak into the 1.4 GHz spectrum, which is suppose to be silent, and does so which sufficient power that you can be pretty sure it's man made.

So if you're looking for an intersting target, you could do worse than those lit up areas.

There is a satellite that listens to solar radiation reflected off the earth to tell different things like ocean salinity. That particular frequency is also used in warfare. This satellite can be used to find areas where electronic countermeasures are in place.

There's a satellite that's measuring ground moisture by looking for radiation in a specific frequency. Some jammers in Ukraine (devices that send noise on radio to make communications impossible for other people) emit radiation in this frequency which makes it visible when looking at the data from the satellite.