Examine source code of treworx

{
  "theme": {
    "images": {
      "theme_frame": "treworx_persona_header.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "treworx",
  "manifest_version": 2,
  "description": "First Persona from treworx.\nWe will make some more ;-)\nPlease contact us for wishes or questions.\nVisit us at <a href=\"https://outgoing.prod.mozaws.net/v1/e82067bfee5bf631f245208c18c902ddb3ff332a568246cb14ccf6a6436dc62f/http%3A//www.treworx.com\" rel=\"nofollow\">www.treworx.com</a>"
}