Yes, \n is the traditional newline/line feed character. However, Windows considers it to be a carriage return (\r) + line feed (\n) for the end of line. Hence CR+LF, instead of just LF. on Windows, and just LF on Linux/unix/MacOS. Also, C/C++/Perl expects LF, but Python/Java expects CR+LF. Not confusing at all. 
Since it’s the default for python (which PlatformIO is written in), I expect it will be the same everywhere, but can be changed in the source code. But this is the reason you have to option to change it in the Arduino IDE serial monitor.
