Examine source code of Better Garmin Graphs

{
  "manifest_version": 3,
  "name": "Better Garmin Graphs",
  "version": "3.1",
  "description": "Zone-colored heart rate and grade-adjusted pace charts for Garmin Connect. See the real effort behind every run.",
  "icons": {
    "48": "icons/small.png",
    "128": "icons/large.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://connect.garmin.com/*"
      ],
      "js": [
        "src/content.js"
      ],
      "css": [
        "src/content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "host_permissions": [
    "https://connect.garmin.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "BetterGarminGraphs@robertkehoe.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}