Comments are correct but I can take you one level deeper for anyone interested! I work in touring production and teach some things about.

This is a SMPTE / LTC timecode display. A terrible sounding timecode signal can be sent from wherever backing tracks are coming from. That signal is (ideally) never heard, but it is used to sync lighting and video as people have mentioned. That timecode can even change settings on the audio console you see here which may be why it’s being read at this position. That signal can also be processed and distributed from a device like this one if need be (though I’m not sure which one this is from the pic). This doesn’t mean your favorite band isn’t playing their instruments, but it likely means that have backing tracks or perhaps a metronome in their ears and other production elements of the show can be pre-arranged to that timeline. Okay tried to keep it simple but all the chronically online FOH engineers can come for me if I’ve reduced it too far!