Native: Uses browser's native Shadow DOM. Check for browser support before enabling it.
ShadowDom: Uses browser’s native Shadow DOM v1 for better cross-browser support and is a shared standard across the browsers. Check the difference between Shadow DOM v0 to v1.
Emulated: Imitates behavior of Shadow DOM to scope the CSS for component and appends to the head.
None: Neither Shadow DOM nor custom implementation, like global CSS which gets appended to the head
Angular uses ViewEncapsulation.Emulated as default encapsualtion mode.