Caches appears at many different levels or places in computer system. You can have on-chip caches, sytem caches and network caches. But the only tag about caches is apparently the tag cpu-cache, which seems very restrictive. Is that intentional, and why? Why not just cache?
The tag cpu-cache is about caches in computer architecture and their relevance to programming. It so happens that we have many questions on that topic, mostly about CPU/memory architecture and about algorithm design.
The tag is definitely not too restrictive — if anything, it's overloaded, as the relevance of CPU caches to algorithm speed and the architecture of memory subsystems are very different topics. Other tags (e.g. algorithms or computer-architecture serve to distinguish these topics.
caching would be a useful tag for a question about the design of caches. I can't find any.
caching and cpu-cache are very different topics. The two tags could coexist, on a question about memory subsystem design (as opposed to what we have in the computer-architecture cpu-cache, which is about analysis of existing designs); there is not much correlation between their domains.
I don't see any reason against that; as far as I know, the term caching is not overloaded (with similarly popular notions). Also, as far as computer science is concerned, we probably don't care where exactly the cache resides.
If we change the tag it shouldd probably be caches to go with our convention of using the plural, or alternatively caching. I'd associate the former more with "How does a cache work?" and the latter with "How do I analyse this algorithm considering caching?" but that may be my personal bias.