Examine source code of Line Effect

{
  "manifest_version": 3,
  "name": "Line Effect",
  "version": "1.0.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{21F18CC1-7F68-4F11-914C-2F93129CEB2C}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "鼠标滑动产生线条拖尾效果",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content-scripts/line-effect.js",
        "content-scripts/fireworks.js"
      ],
      "run_at": "document_end"
    }
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "commands": {
    "toggle-line": {
      "suggested_key": {
        "default": "Ctrl+Shift+F"
      },
      "description": "切换线条效果"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}