Luckily you're a programmer, and can easily change a python script!

That it's so interesting. A lot of people said that to me. But to me it felt more natural to highlight old code. Probably because I had this bias in the back of my mind that old code could be bad code.

In my experience, it's often the new/changed code that is the most interesting. It's often the code that is causing some unexpected bug. 'No one sews a patch of unshrunk cloth on an old garment. Otherwise, the new patch pulls away from the old cloth, and a worse tear is made'

You are ignoring survivor bias.

Old code is mostly good code. It's new code that has varying quality.

Physical things often become darker with age due to dirt or corrosion. Examples are wood and metal, or an old vs. a new wall painted in the same color. They all become darker over time. Therefore I think it't more intuitive to think of darker things as older.