Examine source code of Arrow Mover

{
  "manifest_version" : 2 ,
  "name" : "Arrow Mover",
  "version" : "1.0",
  "description" : "Switch between tabs with Ctrl+Alt+Left and Ctrl+Alt+Right. No setup, no data collection — just move through your tabs with the arrow keys.",
  "icons" : {
    "48" : "icons/icon-48.png",
    "96" : "icons/icon-96.png",
    "128" : "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "arrow-mover@mahauni",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "commands" : {
    "next-tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+Right"
      },
      "description" : "Switch to the next tab"
    },
    "prev-tab": {
      "suggested_key": {
        "default": "Ctrl+Alt+Left"
      },
      "description" : "Switch to the previous tab"
    }
  }
}