This metric is typically tracked internally and probably wouldn't be as public because it could indicate how "buggy" a product is. An easy way to measure this is time spent taking incidents from open -> mitigated -> resolved and treating that as time spent * engineers for amount of impact.

The tricky part would be measuring time spent on hardening and making the business decision on how to quantify product features vs reliability (which I know is a false tradeoff because of time spent fixing bugs but still applies at a hand wavy level)