Examine source code of Edit with Emacs

{
  "name": "Edit with Emacs",
  "version": "1.16",
  "manifest_version": 2,
  "description": "Allow user to edit web-page textareas with Emacs (and other editors).",
  "browser_action": {
    "default_icon": "icons/emacs23-16x16.png"
  },
  "background": {
    "page": "html/background.html"
  },
  "permissions": [
    "tabs",
    "contextMenus",
    "notifications",
    "http://penguin.linux.test/edit/*",
    "http://127.0.0.1/edit/*",
    "clipboardRead"
  ],
  "icons": {
    "128": "icons/emacs.png"
  },
  "options_ui": {
    "page": "fancy-settings/source/index.html",
    "open_in_tab": true
  },
  "web_accessible_resources": [
    "icons/gumdrop.png",
    "icons/emacs23-16x16-red.png"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*",
        "file://*/*"
      ],
      "css": [
        "css/textareas.css"
      ],
      "js": [
        "lib/jquery-3.2.1.min.js",
        "lib/jquery.color.min.js",
        "javascript/textareas.js",
        "lib/mutation_summary.js"
      ],
      "run_at": "document_idle",
      "all_frames": true
    }
  ],
  "commands": {
    "edit-textbox": {
      "suggested_key": {
        "default": "Alt+E",
        "linux": "Alt+E",
        "mac": "Alt+E"
      },
      "description": "Edit the current textarea with Emacs"
    },
    "activate-emacs": {
      "suggested_key": {
        "default": "Ctrl+Shift+E",
        "linux": "Ctrl+Shift+E",
        "mac": "Command+E"
      },
      "description": "Activate Emacs with contents of clipboard"
    }
  }
}