I don’t see that the German vocabulary word “Berg” has morphed in meaning (I know you are not saying this); it has always meant “mountain”. It is etymologically related to “Burg” (fortress), probably because a fortress would usually be built on rising ground. Now “Burg” later also took the meaning “fortified city”, obviously under the influence of Late Latin “burgus”, which again is from Greek “pyrgos” (fortified tower), probably a loan word from Asia Minor. Tacitus is the first to talk about the “Teutoburgiensis Saltus” (“folk-fortress-forrest”), presupposing the name Teutoburgium, and obviously here the Latin word has already mingeled with the Germanic “Burg”. I haven’t been able to find an example for a German place-name, where “-berg” and “-burg” got mixed up, so obviously “Berg” is “Berg” and “Burg” is “Burg” in German place-names. So a place-name ending with “-berg” would be used for a dwelling on or nearby a mountain (or a hill). I don’t know about these elements in other languages like Dutch, Danish or “borough” in English (obviously taken from “Burg”, not “Berg”), but to me the name Katzenberg seems to be of German origin, at least if you suppose it is in fact taken from a place-name. What other possible origins the name may have, I don’t know. If it is a Jewish name, it may well have something to do with the Jewish name Katz (for Kohen Zadik, the high priest). This is an interesting point you are making.