Learn to Read the Source, Luke (2012)
blog.codinghorror.comI find myself returning to this blog post about once a year. It think it has aged pretty well in the decade since it was written.
One thing that definitely did not pan out is being able to understand the source of a website/web app because it is written in JavaScript. Transpiling/minification/etc. without the corresponding source maps makes that near impossible for any app of a reasonable size.