Examine source code of RKO Playlist Player

{
  "manifest_version": 2,
  "name": "RKO Playlist Player",
  "version": "1.3.2",
  "description": "Adds a persistent playlist and music player to Remix.Kwed.Org.",
  "icons": {
    "32": "icons/rko-player-32.png",
    "64": "icons/rko-player-64.png"
  },
  "incognito": "not_allowed",
  "browser_specific_settings": {
    "gecko": {
      "id": "rko-playlist-player@local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage",
    "https://remix.kwed.org/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://remix.kwed.org/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ]
}