Lol, it seems to be a sound system that plays sounds at a frequency that supposedly humans can't hear to calm your bird down. Like the opposite of the rodent deterrents that you plug in and it also emits a high frequency. As a person with sensitive hearing, I can assure you that I can still hear those sounds and it drives me bonkers.
This is what Google translate says:
"No less than 6 years of intensive research has been done (in collaboration with veterinarians) before RelaxoPet was launched. 3.5 years of research has been done in the field of birds and the RelaxoBird is completely focused on the sound level of the bird. The new Relaxobird works with completely new subliminal sound sequences that are not audible to the human ear. In total there are 6 different songs (tracks) that are played by the RelaxoBird. Ideal for birds that quickly suffer from stress, (abandonment) anxiety, or other behavioral problems.
RelaxoBird can help against picking at crooked beaks, if this is a result of stress or anxiety. RelaxoBird can help against screaming, if this is followed by anxiety, separation anxiety or stress. So also ideal when you want to leave the house but your parrot, for example a cockatoo, starts screaming when you leave the house."