The handle is loose (a bit wiggly) and I want to take it off to figure out how to tighten it. Problem is I can't figure out how to take it off...
My guess is it is from mid to late 2000s
You should find a set screw under the small colored plug.
You can remove the red/blue plug with your fingernail. It's just pressed in place. Beneath is an allen bolt (often 5/32). I think that's what is loose. Tighten the bolt, then replace the red/blue plug, and you're done.