The event feed is a live feed of all events happening within Mythic. This is where Mythic records messages for new callbacks, payload creations, users signing in/out, etc
The event feed is located in the "Operations Views" dropdown
The event feed is a running list of all that's going on within an operation. However, you're also able to add your own messages to the event log as a basic form of chat or generic information storage while operating. If Mythic has an error, these will be recorded in the event log with a red background and a button to allow "resolution" of the problem. If you resolve the problem, then the background will change to green. You can also delete and edit messages as needed:
Messages from Mythic will be in a blue font whereas messages from operators will be in a different font. This makes it pretty easy for operator comments to stand out.
You can also filter down these messages with the top right filter as well: