Examine source code of Easy Steam Collection

{
  "version": "0.1.1",
  "manifest_version": 2,
  "name": "Add all addons for steam",
  "short_name": "add-all",
  "permissions": [
    "storage",
    "activeTab",
    "*://*.youtube.com/*"
  ],
  "web_accessible_resources": [
    "data/content_script/youtube.js"
  ],
  "description": "Clicking the green button will add all your addons for steam to your collection.",
  "browser_action": {
    "default_title": "All all addons",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": true,
      "run_at": "document_start",
      "matches": [
        "*://steamcommunity.com/sharedfiles/managecollection/*"
      ],
      "js": [
        "data/content_script/inject.js"
      ]
    }
  ],
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  }
}