There is a difference between "must" and "should". Take this list as an advise on how to become better at understanding the fundamentals. A front end developer

There is a difference between "must" and "should". Take this list as an advise on how to become better at understanding the fundamentals. A front end developer for instance could take html,js, and the DOM as gospel. Or they could try to understand their foundation and how the same concepts apply in different domains (e.g., what and why are the distinctive advantages/shortcomings of js). I prefer the latter and I think it makes me better at my job. Also it is kind of sad when a fellow developer is stuck with a problem that can easily be debugged with some OS knowledge.