This is a terrible Chrome extension for graphing Advent of Code private leaderboard data. Seriously, you probably want to use the Advent of Code Charts extension instead. (Chrome Extension) (Firefox Extension)
Still here? OK, here's how you can install this into Chrome:
You want to pick the directory that contains the manifest.json file. In my case, I have a C:\src\adventofcode-datavis\manifest.json, so I pick C:\src\adventofcode-datavis.
If you don't see the link, refresh the leaderboard page after installing the extension.
