Examine source code of Tweet Shots

{
  "manifest_version": 2,
  "name": "Tweet Shots",
  "version": "1.0.1",
  "description": "Upload screenshots of Tweets from PC to your Google Photos.",
  "permissions": [
    "menus",
    "tabs",
    "notifications",
    "http://localhost/*",
    "storage",
    "https://tweet-shot-api.herokuapp.com/*"
  ],
  "icons": {
    "16": "/images/save-tweet-18.png",
    "32": "/images/save_tweet-36.png",
    "48": "/images/save_tweet-50.png",
    "128": "/images/save_tweet-100.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background-script.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{008c3484-de10-40cc-ba7c-c14adddb6962}"
    }
  }
}