Created by: ffoodd
IE11
While checking #30836, I came across floating labels in IE11 that could just work fine since it supports a vendor prefixed version of ::placeholder-shown and Autoprefixer just does it job…
Preview: https://deploy-preview-30965--twbs-bootstrap.netlify.app/docs/4.5/examples/floating-labels/
Edge
Moreover the Edge workaround uses display: none to hide labels, which is a pitty from an accessibility perspective.
However Edge also concerns v5, so I'll target master for this and it should be backported late (Xref: #30966).