What's this part?!?

1996 kz1000

Hello everyone! Finally got coils installed on custom brackets. At first she didn't want to start. So I started going through all my electrical connections and cleaning them. And then I found this relay and can't for the life of me figure out exactly what it is. It clicks when there is power turned on. Makes me think it's for the starter but the internet doesn't show me anything like this pertaining to the starting system. So please can somebody inform me what I'm looking at here. When I clean the connections on it, the bike finally fired. It looks like it's sad and water for a while in the rubber boot it's in.

After getting the bike started she runs great for about 20 minutes and once everything's up to temperature I start losing power in the higher RPMs and it's slowly works down to where there's next to nothing at all and I have to stop and let the bike cool down. This was happening prior to me getting new coils which I thought was the initial problem. Also noticing backfiring when decelerating from higher RPMs. Please help. Just got the bike up the season and running low on weather!