Matty tends to mix his characters together from various sets. He prefers Genesis 3 giirls over 8, so she is probably from that line.
Take a look at the notes for this pose set, he lists the models used there. https://www.daz3d.com/everyday-poses-for-genesis-3-and-8
In Matty's words
"The girls shape is a custom mix of of 19 different characters plus additional morph packs. Like all my custom girls, I do not share their formulas. Her skin though is Sage for G3F - https://www.daz3d.com/sage-for-genesis-3-female"
But wow, 19 character blended to be 1 character, he really does pretty good job to not make her an abomination, I can't blend more then 4 in same time without the resulting face turn to be weird,so probably he use a lot of face morph to adjust her face