An asterism in Vela, formed from 4 stars. Not one of the 88 constellations.
Larger and dimmer than the real Southern Cross, and mistaken for it often enough to have earned the name. It points nowhere useful.
The False Cross is centred near right ascension 8.9 hours, declination -57°. It lies south of the celestial equator and sits low for northern observers, better the further south you go.
The International Astronomical Union recognises 88 constellations, and they divide the whole sky between them like countries on a map. The False Cross is not one of them — it is a pattern picked out of Vela. That makes it an asterism: a shape people recognise and name, with no official standing whatsoever.
The distinction matters less than it sounds. Asterisms are usually easier to find than the constellations containing them, which is exactly why they survive.
SkyRef can draw the False Cross in its real position for wherever you are — switch on the asterism layer and it appears dashed across the constellations it runs through.