The Mean time to remediation widget is on the ROI dashboard (MAX > Customer portal > ROI tab).
This widget tracks how long it takes to resolve escalated Critical and High findings, measured from escalation to resolution, averaged by month over the selected period. The chart shows the monthly trend as bars, and the two summary tiles show the mean days to remediation (the headline MTTR for the period, averaged across the monthly figures so one unusually busy month doesn't skew the result) and the total count of high and critical findings resolved in the period, across all months shown.
Only escalated findings (the same cohort a customer sees in their Findings and Breaches views) are counted, so the widget's numbers always match what the portal shows elsewhere.