[Vegenoid]

The equivalent of BeeBase’s error in your example would be simply “invalid regex”, which I’d say is still more useful as regex is widely understood and there are many tools that you can give regex to that will tell you what is wrong with it.

[cess11]

No, there's a specificity to "name" and "group" that makes them similar, which is one part of why I settled on this example. The other is that I expected the recipient to have experience with regex and find the example dumb, confirming my position that one can very well demand a basic knowledge of the tool that isn't immediately communicated by it.

Like knowledge of the regex language, or having spent ten minutes skimming through the tutorial part of a PDF manual.

In my experience, how to use a manual is a technique more widely understood than regex. Maybe this impression is wrong, I'd welcome something tangible pointing in another direction if it is.

[jfyi]

If it's any consolation, I (some random guy on the internet) would look for naming conventions in the manual if I was given the error "invalid name".