Examine source code of Jisho Lookup

{
  "name": "Jisho Lookup",
  "version": "1.0",
  "manifest_version": 2,
  "permissions": [
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "48.png",
    "96": "96.png"
  }
}