It is the main part of the verb herunterladen, which means "to download". Alone, laden means "to load". When conjugated for the third person singular, it becomes lädt and the separable prefix moves to the end in a normal sentence.
Usually is meant "software" - only the whole amount of emissions is the "TV-Programm". Today one would download this very rarely because of the ammount of data - and the copyright. One would rather "stream" it for a short time (for one emission).