Retaliation
Definition: the strategic plan the German leaders promised to their people to break the resistance of the opposing military and finish the war on the European Theater.
And I rather quote a couple of relevant lines:
"The retaliation will happen by the unexpected deployment of weapons built yet unknown ways, and which have yet unknown effects, and these surely will suddenly paralyze the enemy's wartime will and resistance. [...] The retaliation maybe won't be executed on the enemy military, but on the civilian population. [...] What would those say, who [...] if the war reached its peak on a history changing day by the metropoli of the Far-West falling into ruins: the Jewmarket of Earth: New York, the center of spiritual leadership: Washington, and the bottom of its materialistic life: Chicago; and then those Anglos who just live a few kilometers away got warned to shed their Plutocrat - Marxist - Judaist system, or suffer the same fate?!"
Szálasi expects the Germans to exploit the yet unknown effects, even with launching their own invasion, first of all against the British isles. They will reconnect the British to Europe, into a Germanic commonwealth.
I'm fairly sure there was already talk in Axis newspapers about the Vergeltung at the end of 1943, probably in vague terms, the Vergeltungswaffen came half a year later in 1944. Their effect wasn't that apocalyptic like in Szálasi's description, but another weapon coming in 1945 which had - it just wasn't deployed by the Germans.
I've no actual knowledge of this but I suspect the German leadership released information to their fellow National Socialist brethren, and probably to the allied governments as well via confidential channels, in order to reassure their faith in their final victory. Especially in those times of the war when the Axis advancement not just stopped, but they were forced to retreat.