vc-annotate in Emacs is a nice tool to see the "maturity" (age) of each line of code in colors. More blue dark, more mature, more red, less mature. This functionality has already been considered to be implemented in MediaWiki (but I don't know if it ever came to be). Usually, in a active project, untouchables lines or functions are very stable (it's applicable to Wiki too - information not disputed tend to be better) and bug-free.
Is there a tool to make a analysis of maturity of a code on Git based on the age of each line? That output something like:
Total lines: 500 Until 1 month lines: 100 1mo-6mo lines: 200 6mo-1yr lines: 100 more than 1yr lines: 100
This could be very useful in active projects (in abandoned maybe it is useless since the entire code would be false-flagged to "mature").