Examine source code of No Retweets

{
  "manifest_version": 2,
  "name": "No Retweets",
  "description": "Hides tweets from people you don't follow from your timeline.",
  "version": "1.1resigned1",
  "icons": {
    "48": "icons/logo_48px.png",
    "96": "icons/logo_96px.png"
  },
  "permissions": [
    "*://twitter.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{db05c111-d26c-482c-9c74-ac12cc1b7b37}"
    }
  }
}