ES6 is still somewhat more popular. It's like a lot of terms that catch on even when they're not officially accurate for what they describe (e.g. 'HTML5' coveri

ES6 is still somewhat more popular. It's like a lot of terms that catch on even when they're not officially accurate for what they describe (e.g. 'HTML5' covering things like WebGL) - it often pays to go with common usage. If the end digit had matched, I suspect it would have worked out better, but with ES2015 and ES6 being equivalent, it's pretty confusing.