What does a device need to enable debug capabilities?

Support for my board was recently added to MBed-OS (https://github.com/ARMmbed/mbed-os/pull/12338) and I’ve been using the prerelease to start my development on the device.
Now I’m wondering, I played a bit with a more popular/mature MCU to get acquainted with mbed-os and I was able to use the “Debug” button in MBed Studio to add breakpoints and whatnot.

However, this button seems to be disabled for my development board in this pre-release version of mbed-os.

So my question boils down to: what does a target need to be able to use the debug capabilities of Mbed-OS and/or Mbed Studio?

I’d be willing to contribute the necessary changes to the main repository if I manage to get this working :slight_smile: