modern German cuckoo clock movement, most likely made by Regula.

From the back plate I can read:

Regula logo

25-77

Made in West-Germany

Serial/patent markings

The 25-77 designation indicates a Regula 25-series movement, one of the most common cuckoo clock movements produced from the 1970s onward.

What it is

1-day chain-driven cuckoo clock movement.

Time and strike train.

Mechanical cuckoo operation.

West German production (before reunification, so roughly 1970s–1980s).