Examine source code of Toggle Pixiv Recommended

{
  "manifest_version": 2,
  "name": "Toggle Pixiv Recommended",
  "version": "1.0",
  "author": "Ao",
  "description": "Adds a button to toggle the obstructive 'Recommended Users' bar on Pixiv without closing it completely.",
  "content_scripts": [
    {
      "matches": [
        "*://*.pixiv.net/*"
      ],
      "js": [
        "PixivRecs.js"
      ]
    }
  ]
}