From 1815-1846 Krakow was a Free City under the tripartite protection of Prussia, Russia, and Austria. In 1846 Austria annexed the statelet.
What if Russia had annexed the city instead?
This will lead to an earlier and greater emnity
Something Russia could use less of in the coming Crimean war of 1853-1855.
OTL Austrians have forsaken the union of three eagles and maintained hostile neutrality against Russia.
And that's
after Nicholas I has saved their bacon from Hungarians in 1849 - out of misguided principled notions that filled his obsolete head.
Now imagine Austrian reaction if there is a feeling Russia stole some rightful Austrian clay from under their noses.
I'm thinking the main effect would be the WHY of it and its repurcussions.
I agree. The WHY would have far greater repercussions than Krakow itself.
Is there a leadership change in Russia?
Are anti-Austrian elements gaining traction in imperial government?
If so, will Austria gain crucial Russian support against Hungarians in 1849?
If not, the map of central Europe changes dramatically. Collapse of one of the Great Powers of its time would send shockwaves across Germanic Union and beyond.
Austria was in the middle of its own revolution in 1848-49, so Austrian rump isn't going to remain a monarchy either. This is a huge win for the historical progress in Europe.
The remaining monarchist governments will be terrified by such blow. "Reaction era" would be much, much harsher than in OTL. With collapse of Austria, remaining Princes/Kings of Germanic Union would rally around Prussia; this could accelerate small German solution and creation of German state by decades.
Expect much clampdown on nationalist movements in Europe and beyond.
Imagine the terror in Britain when 1857 Indian rebellion hits after Hungarians overthrow Austrian empire.