It does, but EmBitz uses GDB (GNU Debugger),
which is the thing that actually does the debugging.
Presumably Femto can also interface with GDB,
as @FManga mentions it in one or two comments in the Femto IDE thread, e.g. here:
Unfortunately I’m not quite sure how, but I expect someone else knows.
The rest of the process should be more or less the same,
interfacing with GDB via a J-Link or SWD interface, facilitated by the PEX to J-Link/SWD thing.