Examine source code of SO Focused

{
  "manifest_version": 2,
  "name": "SO Focused",
  "version": "1.2",
  "description": "Hides distracting sidebar elements on StackOverflow and related sites.",
  "author": "Rob Cowsill",
  "homepage_url": "https://github.com/rcowsill/SO-Focused",
  "icons": {
    "48": "icons/SO-Focused-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.stackoverflow.com/*",
        "*://*.stackexchange.com/*",
        "*://*.superuser.com/*",
        "*://*.serverfault.com/*",
        "*://*.askubuntu.com/*",
        "*://*.stackapps.com/*"
      ],
      "run_at": "document_start",
      "css": [
        "css/hide-distractions.css"
      ]
    }
  ]
}