Most of the questions you ask are covered in the DT documentation:
The macros are generated by a Python script at build time, see the link above for details.
From: users@... <users@...> On Behalf Of henrique.guimaraes via Lists.Zephyrproject.Org
Sent: 18 February 2020 15:08
Subject: [Zephyr-users] Help on Devicetree aliases on eclipse #dts #eclipse #nrf52840