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.
I used royalty free guitar loop from sample pack. I fit loop to beat bpm, changed pitch and cut some parts out of it to make variations. Flute melody, 808 and drums are created by me.
Sample pack KOOKUP GUITAR SAMPLES VOL. 5
Loop name kookup - frenetic 137