Examine source code of Instarss

{
  "manifest_version": 2,
  "name": "Instarss",
  "version": "1.0.1",
  "description": "Adds an RSS button for Instagram account using RSS Bridge",
  "icons": {
    "48": "icons/instarss-48.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "page_action": {
    "default_icon": {
      "19": "icons/instarss-19.png",
      "38": "icons/instarss-38.png"
    },
    "default_title": "RSS Instagram"
  },
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "instarss.js"
    ]
  }
}