Examine source code of StatsHunters

{
  "name": "StatsHunters",
  "version": "3.3.8",
  "description": "Show tiles on Strava route builder",
  "manifest_version": 2,
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.strava.com/maps/*",
        "https://www.strava.com/routes/*/edit*",
        "https://www.komoot.com/*",
        "https://www.komoot.nl/*",
        "https://www.komoot.es/*",
        "https://www.komoot.it/*",
        "https://www.komoot.fr/*",
        "https://www.komoot.de/*",
        "http://brouter.de/brouter-web/*",
        "http://www.brouter.de/brouter-web/*",
        "https://brouter.de/brouter-web/*",
        "https://www.brouter.de/brouter-web/*",
        "https://brouter.m11n.de/*",
        "https://bikerouter.de/*",
        "https://brouter.damsy.net/*",
        "https://*.outdooractive.com/*/routeplanner*",
        "https://ridewithgps.com/*",
        "https://connect.garmin.com/modern/*",
        "https://connect.garmin.com/modern/course/create*",
        "https://connect.garmin.com/modern/course/*",
        "https://connect.garmin.com/app/*",
        "https://connect.garmin.com/app/course/create*",
        "https://connect.garmin.com/app/course/*",
        "https://cycle.travel/map",
        "https://*.mapy.cz/*",
        "https://*.mapy.com/*",
        "https://web.dev.locusmap.app/*",
        "https://web.locusmap.app/*",
        "https://dashboard.hammerhead.io/*",
        "https://dynamic.watch/*/plan*",
        "https://dynamic.watch/plan/*",
        "https://dynamic.watch/plan",
        "https://mapa-turystyczna.pl/*",
        "https://alltrails.com/explore/map/*",
        "https://www.alltrails.com/explore/map/*",
        "https://www.alltrails.com/*/explore/map/*",
        "https://www.alltrails.com/explore/*",
        "https://www.alltrails.com/members/*",
        "https://openrunner.com/*",
        "https://www.openrunner.com/*",
        "https://gpx.studio/*",
        "https://veloplanner.com/*",
        "https://gaiagps.com/map/*",
        "https://www.gaiagps.com/map/*",
        "https://www.plotaroute.com/routeplanner"
      ],
      "js": [
        "statshuntersLoader.js",
        "config.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "options.html"
  },
  "icons": {
    "16": "statshunters-16.png",
    "32": "statshunters-32.png",
    "48": "statshunters-48.png",
    "128": "statshunters-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "browserextension@statshunters.com"
    }
  },
  "web_accessible_resources": [
    "statshuntersRouteOverlay.js"
  ]
}