Examine source code of chord-columnizer

{
  "manifest_version": 2,
  "name": "chord-columnizer",
  "version": "0.3.5resigned1",
  "description": "columnize chord",
  "icons": {
    "48": "icon48.png"
  },
  "permissions": [
    "tabs"
  ],
  "page_action": {
    "default_icon": {
      "48": "icon48.png"
    },
    "default_title": "Columnizer",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://ja.chordwiki.org/*",
        "*://chordsketch.com/*",
        "*://gakufu.gakki.me/*",
        "*://www.ufret.jp/*"
      ],
      "js": [
        "columnize.js",
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{232740a7-f00c-4d3b-833a-b76c83ad5c85}"
    }
  }
}