More discussion/background: https://github.com/whatwg/html/pull/290
Alice Wonder commented
Please implement this. I frequently use _blank as a target because my content often sites other sources the viewer may wish to skim without losing their place in my content, and I was rather shocked to find out the behaviour this attribute adds isn't the default. This is important.
Arda ÖZKAL commented
Please post this on https://connect.microsoft.com/ too.