Examine source code of osu!antihover

{
  "description": "Removes the need to hover over beatmaps. The space is already there. Use it.",
  "manifest_version": 2,
  "name": "osu!antihover",
  "version": "2.2",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "tabs",
    "webRequest",
    "*://*.osu.ppy.sh/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.osu.ppy.sh/*"
      ],
      "js": [
        "antihover.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{02838e80-19ea-47d2-87e1-e5ac31a5cc3a}"
    }
  }
}