Examine source code of SP REST JSON

{
  "description": "Modifies request header for SharePoint REST API calls to get JSON instead of XML.",
  "manifest_version": 2,
  "name": "SP REST JSON",
  "short_name": "SP REST JSON",
  "version": "1.6.0",
  "author": "Daniel Desch",
  "homepage_url": "https://github.com/ddesch/SP-REST-JSON/tree/master/",
  "icons": {
    "16": "icons/16/active.png",
    "32": "icons/32/active.png",
    "48": "icons/48/active.png",
    "64": "icons/64/active.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/16/inactive.png",
      "32": "icons/32/inactive.png",
      "48": "icons/48/inactive.png",
      "64": "icons/64/inactive.png"
    },
    "default_popup": "popup/tabOptions.html"
  },
  "background": {
    "scripts": [
      "SPRESTJSON.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start",
      "css": [
        "JSONViewer/json-viewer.css"
      ],
      "js": [
        "JSONViewer/json-viewer.js",
        "content.js"
      ]
    }
  ],
  "permissions": [
    "<all_urls>",
    "activeTab",
    "tabs",
    "storage",
    "webRequest",
    "webRequestBlocking"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true,
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7284ef85-567a-43f4-ab24-b07dabe8de7e}",
      "strict_min_version": "68.0"
    }
  }
}