Examine source code of Otli - Distraction Blocker

{
  "manifest_version": 2,
  "name": "Otli - Distraction Blocker",
  "short_name": "Otli",
  "version": "1.7.0",
  "version_name": "1.7",
  "description": "Hide distracting content while using powerful platforms",
  "author": "Vadim Gouskov",
  "permissions": [
    "storage",
    "https://*.facebook.com/*",
    "https://*.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Otli"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.facebook.com/*",
        "https://*.youtube.com/*"
      ],
      "run_at": "document_start",
      "css": [
        "content-style.css"
      ]
    },
    {
      "matches": [
        "https://*.facebook.com/*",
        "https://*.youtube.com/*"
      ],
      "run_at": "document_start",
      "js": [
        "js/content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "content-style.css",
    "popup.css",
    "options.css"
  ],
  "icons": {
    "16": "assets/otli-logo-icon-16.png",
    "32": "assets/otli-logo-icon-32.png",
    "48": "assets/otli-logo-icon-48.png",
    "64": "assets/otli-logo-icon-64.png",
    "128": "assets/otli-logo-icon-128.png"
  }
}