Trident got forked/rewritten to Spartan around IE10 and IE11 defaulted to Spartan but fell back to Trident sometimes. Edge was just Spartan (and "IE11 Mode" was its hacky way embed Trident back inside Edge). It's sad that Chromium Edge still has "IE11 Mode" and situations where it keeps Trident alive, but Spartan no longer shows up anywhere. Spartan was pretty good, and obviously under-appreciated. RIP