You can then study the HbbTV application offline. You can find more information about HbbTV here: https://www.hbbtv.org/.
First we need to find a service that contains HbbTV application. In this example I will find a service on Astra 19E.
You can find such service in this list: http://dtvlist.dvbstreamexplorer.com/dvbs.html. Look for 'hbbtv' in feature field.
Or you can do a complete SI scan of Astra 19E with DVBStreamExplorer. After completing SI scan switch to service view and you should see something similar to below.
Scroll to the far right to see features field and look for 'hbbtv'.
Open the tuning window and tune on 11244H where the ORF SPORT+ service can be found.
Open Transport Stream Monitor (DVB) and start scanning. After a few seconds of scanning you should be able to select ORF SPORT+ from service drop-down list.
It will now scan for DSM-CC data. This may take a short while. Once all DSM-CC data has been acquired the Object Carousel tab will be populated with file/folder structure. The content of files will also be shown as ASCII/Hex. Below can be seen partly content of a CSS file named min_portal_1_0_6.css which is part of HbbTV application.
Finally below shows partial content of index.html which is a HTML file also part of HbbTV application.