Austrians get the Airguns technology which enables recruitment for their wind-riflemen. Hungary's basically an Austrian clone in terms of their unit roster, so they probably get that technology, too.

Great Britain gets the Screw Breech or whatever it's called, which enables recruitment for their Ferguson rifles. I'm assuming the Scots, Irish, and the 13 Colonies (not the US) get that technology, too, as they get Fergusons in their unit roster, as well.

The Fergusons and windrifles are, if you didn't already know, insanely good light infantry. I think the techs give prestige, as well.