The product https://mobile.plexonline.com supports printing labels, but the browser does not provide the ability to print labels. This app registers the "zpl" scheme on the device to add label printing capability. When the browser navigates to "zpl://?ip=192.168.33.2&port=9100&data=%5EXA%5EFO20%2C20%5EA0N%2C25%2C25%5EFDHello%20world.%5EFS%5EXZ" the operating system will direct the request to this application, which then extracts:
1. The ip address of the printer
2. The port of the printer
3. The data to be sent to the printer.

The app simply sends the data to the printer at the given ip address and port.