[barkbro]

After reading it twice I'm still not sure what the horizontal axis represents. Is it time in days?

I know this is probably meant to be read by people who know more about the subject than me, but adding some axis labels wouldn't hurt.

[avian]

Time is on the vertical axis (labeled with kernel versions that were released at that time instead of date). Horizontal axis is just an arbitrary bug number. It seems bugs are ordered first by severity and then by time they were fixed.