Examine source code of Alt-shift

{
  "manifest_version": 2,
  "name": "Alt-shift",
  "version": "0.3",
  "author": "Real pradeep",
  "description": "hold alt shift and the desired number to switch the tab place",
  "background": {
    "scripts": [
      "Alt-shift.js"
    ]
  },
  "icons": {
    "16": "assests/icon/16.png",
    "32": "assests/icon/32.png",
    "48": "assests/icon/48.png",
    "96": "assests/icon/96.png",
    "128": "assests/icon/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "Hellopradeep69@gmail.com",
      "strict_min_version": "58.0"
    }
  },
  "commands": {
    "Alt_shift_1": {
      "suggested_key": {
        "default": "Alt+Shift+1"
      },
      "description": "Move tab to 1"
    },
    "Alt_shift_2": {
      "suggested_key": {
        "default": "Alt+Shift+2"
      },
      "description": "Move tab to 2"
    },
    "Alt_shift_3": {
      "suggested_key": {
        "default": "Alt+Shift+3"
      },
      "description": "Move tab to 3"
    },
    "Alt_shift_4": {
      "suggested_key": {
        "default": "Alt+Shift+4"
      },
      "description": "Move tab to 4"
    },
    "Alt_shift_5": {
      "suggested_key": {
        "default": "Alt+Shift+5"
      },
      "description": "Move tab to 5"
    }
  }
}