A simple trash box. Has the function of storing away and safeguarding unneeded data files. It's a garbage can. In Passionlip's case, the icon is set right in the middle of her chest for some reason.
To put it frankly, an imaginary space pocket into which you can put anything as long as it's as trash. If it is dust data that Passionlip has crushed, she can stow away an infinite amount, regardless of capacity.
Though it seems contradictory, it seems even objects that exceed Passionlip's own memory storage can be thrown into this valley.
At first glance, this appears to be a convenient function, but because dust data cannot be returned to its original form, it's an utterly useless function. It appears that Passionlip acquired this unique structure because she is of the type of girl who bottles her feelings up inside, leading to self-destruction and self-harm.