Examine source code of Calmer Internet

{
  "manifest_version": 2,
  "name": "Calmer Internet",
  "version": "1.3.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "calmerinternet@lukebriggs.dev"
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/16.png",
      "24": "icons/24.png",
      "32": "icons/32.png"
    },
    "default_title": "Calmer Internet"
  },
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://*.twitter.com/*",
        "*://twitter.com/*",
        "*://*.instagram.com/*"
      ],
      "js": [
        "calmer.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "*://*.youtube.com/*",
    "*://*.twitter.com/*",
    "*://twitter.com/*",
    "*://*.instagram.com/*",
    "storage",
    "webRequest",
    "webRequestBlocking"
  ],
  "description": "Provides a calmer internet experience. Removes comments and various recommendation elements from Twitter, YouTube, Instagram.",
  "options_ui": {
    "page": "options.html"
  }
}