Whilst not directly related to this, I have spoken (https://www.smashingmagazine.com/2019/07/javascript-knowledge-reading-source-code/ https://www.smashingmagaz

Whilst not directly related to this, I have spoken (https://www.smashingmagazine.com/2019/07/javascript-knowledge-reading-source-code/ https://www.smashingmagazine.com/2019/07/javascript-knowledg...) and written (https://www.smashingmagazine.com/2019/07/javascript-knowledge-reading-source-code/ https://www.smashingmagazine.com/2019/07/javascript-knowledg...) about reading source code. If possible (either via docs or guidance from other developers), I find a major API and then follow it to its end point. You will usually come across other major pieces of the codebase this way and you can make a note of them if you wish to do further digging.