Ah! Thank you Mr. Hicks. That information helped me find this page which lists the alternative names:
Originally Posted by CameraQuest
sold under a variety of names including Kobalux, Avenar, Bower and Pasoptik -- among others.
thanks also to all the other respondees of course.
The 25 would be attractive were it not a bit oo close to the 28s I already own.
I think Contax-M adapters probably cost as much as a lens.
And yes, I was thinking of the older CZ lenses.