The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
all loops are been edited with ableton simpler or chopped and processed in a creative way
Sample pack waveform recordings old skool tech
Loop name wr-ost-music-125-25