Examine source code of yt-nhp

{
  "manifest_version": 2,
  "name": "yt-nhp",
  "version": "1.0",
  "description": "YouTube no hover-preview on videos",
  "icons": {
    "48": "icons/yt-nhp-48.png",
    "96": "icons/yt-nhp-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/watch*"
      ],
      "js": [
        "yt-nhp.js"
      ]
    }
  ]
}