This is a tiny addon I wrote for dumping out what addon events fire from doing something. Like, if I want to see what events are associated with activating a Hearthstone.

To use it, first leave town and get someplace remote where nothing is fighting. Bring a friend if you need to reproduce what you want to log. Then enter this slash command in the chat window:

/run EventTracer.RegisterAllEvents(true)

and hit enter. Then do what it is you want to watch. You'll see tons of stuff being printed to the chat window.

Once you've done what you want to inspect, enter this:

/run EventTracer.RegisterAllEvents(false)

Then sift through all the spew to see what looks related to what you did. If the only relevant lines are from COMBAT_LOG_EVENT or COMBAT_LOG_EVENT_UNFILTERED, then there's no way for NeedToKnow to efficiently watch for that event happening. I recommend a chat window addon like Chatter to help with this (especially for being able to copy text from the chat history.)