Examine source code of Jetbrains Mono Scratch

{
  "manifest_version": 2,
  "name": "Jetbrains Mono Scratch",
  "homepage_url": "https://github.com/errplanedev/jbmono-scratch",
  "version": "1.0",
  "description": "A Firefox userstyle to make the font Jetbrains Mono.",
  "content_scripts": [
    {
      "matches": [
        "*://scratch.mit.edu/*"
      ],
      "js": [
        "apply.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "monoscratch@errplane.dev",
      "strict_min_version": "42.0"
    }
  }
}