[k__]

You don't need all of these concepts on an everyday basis.

If you don't use ES5 stuff that was replaced in newer versions, things get much simpler.

let, =>, === etc.

[technion]

Despite the submitted title containing "to help developers master", the actual Github page title contains "every JavaScript developer should know."

I think that casts this post in a different light. If the repo's intent is that "every JS developer should know" everything on this list, the context of this discussion changes.