Examine source code of ctrl_tabs

{
  "manifest_version": 2,
  "name": "ctrl_tabs",
  "version": "0.2",
  "description": "Switch tabs using Ctrl instead of Alt. Intended for i3 users.",
  "icons": {
    "48": "icons/icon.png"
  },
  "background": {
    "scripts": [
      "ctrl_tabs.js"
    ]
  },
  "commands": {
    "1_tab": {
      "suggested_key": {
        "default": "Ctrl+1"
      }
    },
    "2_tab": {
      "suggested_key": {
        "default": "Ctrl+2"
      }
    },
    "3_tab": {
      "suggested_key": {
        "default": "Ctrl+3"
      }
    },
    "4_tab": {
      "suggested_key": {
        "default": "Ctrl+4"
      }
    },
    "5_tab": {
      "suggested_key": {
        "default": "Ctrl+5"
      }
    },
    "6_tab": {
      "suggested_key": {
        "default": "Ctrl+6"
      }
    },
    "7_tab": {
      "suggested_key": {
        "default": "Ctrl+7"
      }
    },
    "8_tab": {
      "suggested_key": {
        "default": "Ctrl+8"
      }
    },
    "9_tab": {
      "suggested_key": {
        "default": "Ctrl+9"
      }
    },
    "last_tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+0"
      }
    },
    "left_tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+H"
      }
    },
    "right_tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+L"
      }
    },
    "close_tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+Q"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c2e013df-64f1-4c22-8683-64b230f6e393}"
    }
  }
}