Examine source code of BC100 Autofill

{
  "manifest_version": 2,
  "name": "BC100 Autofill",
  "description": "Autofills your BahnCard 100 number and birthday into the passenger rights claim form.",
  "version": "0.4.1",
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon@2x.png"
  },
  "browser_action": {
    "default_title": "__MSG_iconAction__"
  },
  "default_locale": "en",
  "content_scripts": [
    {
      "matches": [
        "https://www.bahn.de/buchung/fahrgastrechte?einstiegtyp=BC100",
        "https://www.bahn.de/buchung/fahrgastrechte?lang=*&einstiegtyp=BC100",
        "https://int.bahn.de/*/buchung/fahrgastrechte?einstiegtyp=BC100"
      ],
      "js": [
        "content_script.js"
      ]
    },
    {
      "matches": [
        "https://www.bahn.de/buchung/kundenkonto/bahncard",
        "https://int.bahn.de/*/buchung/kundenkonto/bahncard",
        "https://www.bahn.de/buchung/kundenkonto/bahncard?lang=*"
      ],
      "js": [
        "acquire_bcnum.js"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "options_ui": {
    "page": "options/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "bc100-autofill@iw0.name"
    },
    "gecko_android": {
      "strict_min_version": "113.0"
    }
  },
  "background": {
    "scripts": [
      "bg.js"
    ],
    "persistent": false
  }
}