Examine source code of RESTer

{
  "manifest_version": 2,
  "name": "RESTer",
  "version": "4.15.0",
  "description": "A REST client for almost any web service.",
  "author": "Jan Kühle",
  "homepage_url": "https://github.com/frigus02/RESTer",
  "icons": {
    "48": "images/icon48.png",
    "96": "images/icon96.png"
  },
  "permissions": [
    "activeTab",
    "downloads",
    "storage",
    "unlimitedStorage",
    "<all_urls>"
  ],
  "optional_permissions": [
    "cookies",
    "webRequest",
    "webRequestBlocking"
  ],
  "background": {
    "scripts": [
      "background/bundle.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icon16.png",
      "24": "images/icon24.png",
      "32": "images/icon32.png"
    },
    "theme_icons": [
      {
        "dark": "images/icon16.png",
        "light": "images/icon-light16.png",
        "size": 16
      },
      {
        "dark": "images/icon24.png",
        "light": "images/icon-light24.png",
        "size": 24
      },
      {
        "dark": "images/icon32.png",
        "light": "images/icon-light32.png",
        "size": 32
      }
    ]
  },
  "applications": {
    "gecko": {
      "id": "rester@kuehle.me",
      "strict_min_version": "63.0"
    }
  }
}