Examine source code of Healthy Surf

{
  "manifest_version": 2,
  "name": "Healthy Surf",
  "version": "1.4",
  "description": "Remove negativity, politics, controversial current events, and social issues from reddit, hacker news, Youtube, Twitter, Facebook, and more. Blocks both by keywords and subreddit on reddit.",
  "icons": {
    "48": "icons/bottle-tonic-plus-outline.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/bottle-tonic-plus-outline.png",
    "theme_icons": [
      {
        "light": "icons/bottle-tonic-plus-outline-light.png",
        "dark": "icons/bottle-tonic-plus-outline.png",
        "size": 32
      }
    ],
    "default_title": "Healthy Surf",
    "default_popup": "popup/menu.html"
  },
  "background": {
    "scripts": [
      "assets/jquery-3.2.0.min.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/r/all*",
        "*://*.reddit.com/",
        "*://*.youtube.com/*",
        "*://twitter.com/*"
      ],
      "js": [
        "assets/jquery-3.2.0.min.js",
        "healthysurf.js"
      ]
    }
  ]
}