Examine source code of You No Cards

{
  "name": "You No Cards",
  "version": "1.0.8resigned1",
  "description": "Hide youtube end cards, which are displayed at the end of youtube videos",
  "applications": {
    "gecko": {
      "strict_min_version": "57.0",
      "id": "{450542d6-67d0-4975-aee1-ca1464e1ff6f}"
    }
  },
  "background": {
    "scripts": [
      "libs/control.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "libs/system.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "images/icon16.png",
    "24": "images/icon24.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "19": "images/icon24.png",
      "38": "images/icon48.png"
    },
    "default_title": "You No Cards"
  },
  "permissions": [
    "storage",
    "tabs",
    "*://*/*"
  ],
  "manifest_version": 2,
  "web_accessible_resources": [
    "themes/simple.css",
    "libs/system.js"
  ]
}