Examine source code of SKC

{
  "manifest_version": 2,
  "author": "Timo Schinkel",
  "version": "0.1",
  "name": "SKC",
  "description": "Calculates your \"Steven Kruijswijk Coefficient\" for Strava rides and shows it on your Strava ride page.",
  "homepage_url": "https://github.com/timoschinkel/skc",
  "content_scripts": [
    {
      "matches": [
        "https://www.strava.com/activities/*"
      ],
      "js": [
        "src/inject_into_strava.js"
      ]
    }
  ],
  "icons": {
    "16": "assets/16x16.png",
    "48": "assets/48x48.png",
    "128": "assets/128x128.png"
  }
}