Examine source code of Cauldron20

{
  "manifest_version": 3,
  "name": "Cauldron20",
  "version": "2.0.0",
  "description": "Extension to incorporate D&D Beyond character into Cauldron VTT.",
  "icons": {
    "128": "icon128.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "permissions": [
    "tabs",
    "scripting",
    "storage"
  ],
  "host_permissions": [
    "https://character-service.dndbeyond.com/character/v5/character",
    "https://www.cauldron-vtt.net/adventure/*",
    "https://www.cauldron-vtt.net/character/new",
    "https://www.cauldron-vtt.net/character/weapon/*",
    "https://www.cauldron-vtt.net/character/*",
    "https://www.cauldron-vtt.net/character"
  ],
  "action": {
    "default_icon": "icon128.png",
    "default_popup": "html/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.cauldron-vtt.net/character/new",
        "https://www.cauldron-vtt.net/character/**"
      ],
      "js": [
        "js/cauldronNewCharacter.js"
      ]
    },
    {
      "matches": [
        "https://www.cauldron-vtt.net/adventure/*",
        "https://www.cauldron-vtt.net/adventure"
      ],
      "exclude_matches": [
        "https://www.cauldron-vtt.net/adventure"
      ],
      "js": [
        "js/adventure.js"
      ],
      "css": [
        "css/characterSheet.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "cauldron20@example.org"
    }
  }
}