Examine source code of ShelfScan

{
  "manifest_version": 3,
  "version": "0.6.3",
  "name": "ShelfScan",
  "description": "Update BGG & BGG collection using ShelfScan",
  "icons": {
    "48": "icons/shelfscan-48.png",
    "64": "icons/shelfscan-64.png",
    "128": "icons/shelfscan-128.png",
    "256": "icons/shelfscan-256.png",
    "512": "icons/shelfscan-512.png"
  },
  "background": {
    "scripts": [
      "background/scripts.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://extensionpay.com/*"
      ],
      "js": [
        "content_scripts/content-0.js"
      ],
      "run_at": "document_start",
      "css": []
    },
    {
      "matches": [
        "*://*.boardgamegeek.com/*",
        "https://*.shelfscan.io/*"
      ],
      "js": [
        "content_scripts/content-1.js"
      ],
      "css": [
        "content_scripts/content-1.css"
      ],
      "run_at": "document_idle",
      "all_frames": true
    }
  ],
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "shelfscan-ext@shelfscan.io"
    }
  },
  "author": "j5bot",
  "web_accessible_resources": [
    {
      "resources": [
        "content_scripts/styles.7b00e0a9.css"
      ],
      "matches": [
        "https://extensionpay.com/*"
      ]
    },
    {
      "resources": [
        "content_scripts/styles.7b00e0a9.css"
      ],
      "matches": [
        "*://*.boardgamegeek.com/*",
        "https://*.shelfscan.io/*"
      ]
    }
  ]
}