Kconfig is a configuration language developed for configuring the Linux kernel. Zephyr and nRF Connect SDK use this language for configuring its subsystems at build time, with the nRF Connect SDK implementing several additions on top of it.
Kconfig is structured into a hierarchical tree of configuration options, with most options linked to a configuration entry in the Kconfig files. These entries are often called symbols.
To learn more about Kconfig, read the following pages:
- Official Kconfig documentation
- Zephyr's Configuration System pages
- nRF Connect SDK configuration and build system overview