Examine source code of Tab arrow switcher

{
  "name": "Tab arrow switcher",
  "description": "Switch tab with Ctrl + Arrow keys",
  "version": "1.0.1",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "tabarrowswitcher@lulonaut",
      "strict_min_version": "90.0"
    }
  },
  "commands": {
    "tab-left": {
      "suggested_key": {
        "default": "Ctrl+Left"
      },
      "description": "Switch to the left tab"
    },
    "tab-right": {
      "suggested_key": {
        "default": "Ctrl+Right"
      },
      "description": "Switch to the right tab"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}