Examine source code of Map 5k

{
  "name": "Map 5k",
  "description": "Create custom maps of parkruns",
  "version": "0.0.2resigned1",
  "manifest_version": 2,
  "author": "Daniel Patrick",
  "applications": {
    "gecko": {
      "id": "{53d71fb8-fb0c-4065-acdf-593442e9995e}"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "unlimitedStorage",
    "https://www.parkrun.com/wp-content/themes/parkrun/xml/geo.xml",
    "https://www.parkrun.org.uk/wp-content/themes/parkrun/xml/geojuniors.xml"
  ],
  "options_ui": {
    "page": "options/options_page.html",
    "browser_style": false,
    "chrome_style": false
  },
  "background": {
    "scripts": [
      "assets/js/browser-polyfill.min.js",
      "background_scripts/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.parkrun.org.uk/results/athleteeventresultshistory/?*athleteNumber=*&eventNumber=0"
      ],
      "js": [
        "assets/js/browser-polyfill.min.js",
        "lib/openlayers/ol.js",
        "content_scripts/race_time.js",
        "content_scripts/map_data.js",
        "content_scripts/map_icons.js",
        "content_scripts/map_ui.js",
        "content_scripts/map_controller.js"
      ],
      "css": [
        "lib/openlayers/ol.css",
        "content_scripts/map_ui.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_title": "Map 5k - Free weekly 5k events mapped",
    "default_popup": "browser_actions/popup_menu.html",
    "default_icon": {
      "16": "assets/images/logo/map-marker-logo-16.png",
      "32": "assets/images/logo/map-marker-logo-32.png",
      "48": "assets/images/logo/map-marker-logo-48.png",
      "96": "assets/images/logo/map-marker-logo-96.png",
      "128": "assets/images/logo/map-marker-logo-128.png"
    }
  },
  "icons": {
    "16": "assets/images/logo/map-marker-logo-16.png",
    "32": "assets/images/logo/map-marker-logo-32.png",
    "48": "assets/images/logo/map-marker-logo-48.png",
    "96": "assets/images/logo/map-marker-logo-96.png",
    "128": "assets/images/logo/map-marker-logo-128.png"
  }
}