One axis, two kinds of event
The timeline shows errors and changes on the same line, newest first. That is the whole idea: when an error starts, the change right before it is the first suspect. A fatal that debuts minutes after a plugin update is no longer a mystery.
Grouping
Identical errors are folded into one row with a count and a first/last-seen time. Expand a row to see every occurrence, the file and line, and the redacted message.
Filtering
Filter by Errors, Changes or Everything, by severity, and sort by most recent or most severe. Use it to answer a specific question — “what changed on the day the checkout broke?”