You will also find cases where if you rip a CD, the final song is unusually longer in duration than the rest as a single file contains a gap of certain minutes before the hidden track appears. The purpose is probably to hide the song from a casual listener, just like the mid- and end- credit scenes in Marvel movies.
Eg: (I searched for a famous example) Nirvana’s bonus track Endless, Nameless makes the last song 10:30mins long.
Also, HIM’s Greatest Love Songs Vol. 666 has 56 silent tracks before the track66 begins. It was weird to see those many files in my folder 
@the_termin8r I can tell you it will deaf be ‘silence’ (Bad Joke, but I had a chuckle 
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