Examine source code of Randomize Case

{
  "manifest_version": 2,
  "name": "RanDOmiZe cASe",
  "version": "1.0.0",
  "description": "An addon that randomizes the case of your selected text",
  "permissions": [
    "activeTab",
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4e62bae5-8935-4f50-ad80-ea836c5bb306}"
    }
  }
}