...Looks small enough to patch though
I would throw it out, it will crack more at the next bump.
Not that is dangerous, but it may leave you without saddle in the middle of a long ride.
I was learning to nose-pivot with my MTB.
And once felt hard with all my weight(well...67kg) on the saddle.
Both rails cracked, absorbing most of the shock instead of my butt.
The saddle stayed in place, not rigid nor rideable anymore, but not a carbon explosion either.
I contacted EC90 by aliexpress, and they did send me one free + a small shipping.
Now I stocked 2 of them in case I break one again.
We could ask to make the rails with a kevlar blend like on some expensive models.