Sometimes errors, typos for example, are reported in multiple locations but the correction is elsewhere. ... That means I’d expect a source code for ab Arduino project to be like 100 kB at most.

Official Arduino Example Tutorials: The Arduino computer software is loaded with tons of examples for you to use in your own code or to run through as a learning experience.

It only applies to certain microcontrollers, but he provides example Arduino code showing how handy this can be for battery-powered projects. The usual way to measure VCC is simple, ...