Examine source code of osuWebCollections

{
  "manifest_version": 2,
  "name": "webCollections",
  "version": "0.1",
  "description": "wip webCollections addon",
  "icons": {
    "48": "icons/webCollections-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "webCollections@shaddy.dev",
      "strict_min_version": "57.0"
    }
  },
  "permissions": [
    "nativeMessaging",
    "downloads",
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/webCollections-48.png",
    "default_title": "webCollections"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://osu.ppy.sh/beatmapsets/*"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ]
}