Now, it seems the same API exists for Windows 10 Mobile as well and while a demo is available for opening of “multiple windows of same app”, split-screen multitasking is not confirmed yet.
We have reached to the VLC dev, who has posted the above demo about split-screen multitasking possibility on Phablets.
@ThomasNigro But new window doesn’t show up in same view like on Tablets. Is that possible on phablets?
— Kamal Mishra (@MishraKamalN) July 19, 2015