It doesn’t mean Bibi has won anything. It just means that the parties in his coalition are going to remain united for now.
It means the right bloc would prefer yet another election to a unity government, and Netanyahu seems to agree with them. But it’s just an opening bargaining position.
My guess is that Liberman joins the Leftist parties, and the Left makes a deal with Arabs not to obstruct, leaving a minority government headed by Gantz.
Everyone is talking about a national unity government. I assume that whoever is PM, the other guy would be the deputy and would also get the Foreign or Defense Ministry in it.