I am curious about something. Why don't people build their code on the backend? I've seen people worry about build files/size on the front-end (e.g. when building react applications) but have never heard of building it on the backend. As for my search, can't really find anything about it on the internet. Only thing I know that might be related is: I've seen the autoload files in PHP being built or something (read about it here still not very sure)
P.S. - By build I mean creating production ready, optimized files.