Examine source code of Character Identifier

{
  "applications": {
    "gecko": {
      "id": "char-identifier@dbaron.org"
    }
  },
  "author": "L. David Baron",
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "description": "This extension adds a context menu item for selected text that provides more information (from the Unicode database) about the characters selected.",
  "homepage_url": "https://dbaron.org/mozilla/char-identifier/",
  "icons": {
    "48": "icon-48.png",
    "96": "icon-96.png"
  },
  "manifest_version": 2,
  "name": "Character Identifier",
  "permissions": [
    "contextMenus"
  ],
  "version": "0.2.3"
}