Examine source code of Spoutly

{
  "description": "All the latest news!",
  "manifest_version": 2,
  "name": "Spoutly",
  "version": "0.0.0.2resigned1",
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/open-my-page-button",
  "icons": {
    "16": "./images/icon_16.png",
    "48": "./images/icon_48.png",
    "128": "./images/icon_128.png"
  },
  "background": {
    "scripts": [
      "./background.js"
    ]
  },
  "browser_action": {
    "default_icon": "./images/icon_48.png"
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c18f3639-0b09-4265-9727-e6ddfddcd498}"
    }
  }
}