How was Miku dark append tuned like this?!!??!

[m170]

This song called Poetry of the Heart was made with miku dark append

and another song by same producer called Erica also using dark

I'm just so fascinated by it?? It sounds so different. I ALMOST wouldn't have known that it was miku dark if not for the title of the song when i first heard it at the time. Maybe thats just me lol I'm making such a big deal out of it but I'm just so amazed by it lol. her voice sounds super smooth and "round" and more rich than most songs using miku dark.
Waaa im so obsessed with this voice I'm just amazed by it ahh its like magic lol like wow how was this tuned?? like what??? sorcery

 

[Pixys]

although i dont have miku's dark vb..im pretty sure its maybe note-tuning? if done correctly it can make any vb sound great (or could be pitch-bend tuning...harder to use IMO but )