19thC German Eagle Mark Porcelain Finely Hand Painted Mug Cup Antique KPM Russia

An antique 19th century finely painted porcelain mug or cup. There's a partial impressed mark on the bottom that looks (to me) like an eagle holding a scepter - I don't know this mark, possibly German or Austrian or Russian? The mug is just over 3.25 inches tall.

It is in excellent condition with no chips, no cracks, no repairs - just some gold wear. There are some underglaze manufacturing flaws on the rim, and some underglaze scratches in the porcelain (it was made like this). Please see the photos for details.