Examine source code of GLS Invoice Parser

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "0.3",
  "homepage_url": "https://kkrach.de/gls_invoice_parser/",
  "icons": {
    "48": "icons/gls-invoice-parser-48.png",
    "96": "icons/gls-invoice-parser-96.png"
  },
  "default_locale": "en",
  "content_scripts": [
    {
      "matches": [
        "*://*.gls-online-filiale.de/*"
      ],
      "js": [
        "main.js",
        "parser.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "gls_invoice_parser@kkrach.de"
    }
  }
}