To see all of the nRF Kconfig extension's commands, open the Command Palette and type nRF Kconfig.
For example, the nRF Kconfig: Kconfig: Show Config GUI command opens the Kconfig GUI and corresponds to the nRF Kconfig GUI action in the Actions View.
To see all of the nRF Kconfig extension's settings, open the Settings editor and type nrf-kconfig.