Examine source code of GitHub Extension

{
  "name" : "GitHub Extension",
  "description" : "GitHub Browser Extension",
  "version" : "1.1.0",
  "manifest_version" : 2 ,
  "content_scripts" : [
    {
      "matches" : [
        "https://*/*" ,
        "http://*/*" 
      ],
      "js" : [
        "inject.js" 
      ]
    }
  ],
  "browser_action" : {
    "default_title" : "GitHub Extension",
    "default_popup" : "index.html"
  },
  "permissions" : [
    "https://apps.saptarsheebhowmick.in/*" 
  ],
  "icons" : {
    "16" : "icons/16.png",
    "32" : "icons/32.png",
    "48" : "icons/48.png",
    "128" : "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c9e67e8d-63e4-46ea-85d6-108015663cdf}"
    }
  }
}