Seeed XIAO nRF52840 Sense define value equivalent to ARDUINO_ARCH_NRF52840

When using the embed-enabled board manager (Seeed nRF52 mbed-enabled Boards), I can use the following code to check for the board:

#if defined(ARDUINO_ARCH_NRF52840)

But with the normal board manager (Seeed nRF52 Boards) this one is not defined. I unsuccessfully tried different build.board values from here:

Unfortunately I couldn’t figure out how to get to the new value. I assume there must be some alternative value based on the board name?