Examine source code of UG Columns

{
  "manifest_version": 2,
  "name": "UG Columns",
  "version": "1.0",
  "description": "Makes Ultimate Guitar use columns for the music view.",
  "icons": {
    "32": "icons/guitar.svg",
    "48": "icons/guitar.svg",
    "64": "icons/guitar.svg",
    "96": "icons/guitar.svg",
    "128": "icons/guitar.svg",
    "245": "icons/guitar.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://tabs.ultimate-guitar.com/tab/*"
      ],
      "css": [
        "ug_columns.css"
      ]
    }
  ]
}