As others have said, ETC has setups like these at their test benches and what not. However, this is several times larger than the ones I have seen. If it's not a dimmer or DMX output tester at ETC (or somewhere else, who knows) I'd guess some sort of ghost load, though that still seems like a lot of circuits.
Based on the numbered bulb envelopes and what looks like multicable coming off the top, I'd say it is used to test dimmer racks. If the channel is good, the bulb illuminates.
Based on the numbered bulb envelopes and what looks like multicable coming off the top, I'd say it is used to test dimmer racks. If the channel is good, the bulb illuminates.