GitLab of Theseus - new chart type

Description

As a project evolves, does the new code just add on top of the old code? Or does it replace the old code slowly over time?

I'd like to propose to add to GitLab a chart that will show how much code lines are still present as times goes by.

For popular open source projects you can see examples of this chart below.

Git

Rails

Linux kernel

Links / references

• https://github.com/erikbern/git-of-theseus
• https://erikbern.com/2016/12/05/the-half-life-of-code.html