The ability to scroll back via a TV's to TV programs which have already
been shown or even which are already mid way through. Is the program
list served up via the antenna, or the connection to the Internet, or
maybe a mixture of both?

The problem I am curious about is lots of LG TV owners, including
myself, complaining that often the (back in time) button is absent
from the EPG. Is this presented from the antenna, or from an Internet
server somewhere?

When missing, sometimes a channel rescan brings it back and its the
only way to bring the symbol back, often turning the set off then on
looses the , though not always, sometimes it proves impossible to get
the for hours and days.