Examine source code of Gitcolor - Github Themer

{
  "name" : "Gitcolor - Github Contribution Themer",
  "short_name" : "Gitcolor",
  "version" : "0.1.2",
  "description" : "Set different themes to the GitHub contribution graph",
  "permissions" : [
    "storage" ,
    "activeTab" 
  ],
  "content_scripts" : [
    {
      "matches" : [
        "*://github.com/*" 
      ],
      "js" : [
        "content.js" 
      ]
    }
  ],
  "web_accessible_resources" : [
    "assets/theme.svg"
  ],
  "icons" : {
    "24" : "assets/favicon-24x24.png",
    "32" : "assets/favicon-32x32.png"
  },
  "browser_action" : {
    "browser_style": true,
    "default_popup" : "popup.html"
  },
  "manifest_version" : 2 ,
  "browser_specific_settings": {
    "gecko": {
      "id": "{79bbd2bd-713d-470c-9e0e-015dc5e531ac}"
    }
  }
}