Examine source code of OALDTrans

{
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "description": "Context menu to translate with OALD",
  "icons": {
    "64": "icon.png"
  },
  "manifest_version": 2,
  "name": "OALDTrans",
  "permissions": [
    "tabs",
    "menus"
  ],
  "version": "2"
}