This is addtional content that enables the following songs:

Exteeend!!
STNC
Mishery(Dankagu Edit)
・ー・・ ーーー ・・・ー ・
Midnight Syndrome
March of the Broken Dolls (SA ver.)
Amorphous Avatar
sharp edge
Crepusculum
Desire Drive

More details on the official game page of Extra Song Pack 7 ...