What is considered (Zephyr) OS Core?

[AnttiLukats]

From the rules: "The Zephyr 1.13 release should be used and can only be modified in a way that does not touch the OS core" - however it is not clear what is considered as OS (Zephyr RTOS) core!

if we assume that \zephyr\arch\riscv32\core

belongs to OS core, then we can still modify it indirectly as the files in that folder do use some MACROS defined elsewhere (as example SOC_ERET) if we REDEFINE that macro it would "change" the OS core and could disqualify our entry?

It is also to be assumed that lots of other files belong to OS core - but the set of "core" and not core files is not clear.