Tacitly: "mistakes were made..."
"Microsoft lists what isn't in Edge in this blog post. Highlights of those removed technologies include:Microsoft Edge Browser Jettisoning Older Technologies for Better Security -- Redmondmag.com
- ActiveX -- HTML 5 takes care of the need for ActiveX controls, according to Microsoft, although Edge will still have built-in Adobe Flash support and PDF support
- Document Modes -- Edge will have a single document mode, while IE will still be around for organizations that need the legacy code support
- Vector Markup Language - it's supplanted by Scalable Vector Graphics now, according to Microsoft"