Plugin Precompile Header Mystery

So, I have resolved a compile error issue after making my first c++ plugin after spending some time searching in here. The problem was perfectly resolved by putting ‘#include “Engine.h”’ statement in the private precompile header, which ends with PCH.h"

Why would we need this now for plugins while it wasn’t required for the main module? I checked build settings, and I couldn’t figure out any significant difference.

As a side note, it would be best if this particular line code can be automatically put into the precompile header when plugin is generated by the editor. I used blank for this, though I’m not sure if this matters.