Examine source code of HTML Gmail in Sidebar

{
  "manifest_version": 2,
  "name": "HTML Gmail in Sidebar",
  "description": "Displays HTML only version of Gmail in the sidebar.",
  "version": "1.0",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "strict_min_version": "60.0",
      "id": "{d27465f8-080f-46b6-92b0-9aa8931fa0c9}"
    }
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "sidebar_action": {
    "default_icon": {
      "48": "icons/48x48.png",
      "96": "icons/96x96.png"
    },
    "default_title": "Gmail",
    "default_panel": "sidebar/panel.html"
  },
  "icons": {
    "48": "icons/48x48.png",
    "96": "icons/96x96.png"
  },
  "commands": {
    "_execute_sidebar_action": {
      "suggested_key": {
        "default": "Alt+Shift+G"
      },
      "description": "Toggle the Gmail sidebar."
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/16x16.png",
      "32": "icons/32x32.png"
    }
  }
}