How can I create, without a verbatim environment, these nice boxes that the
Fancyvrb package produces:
The sibling package
Fancybox (by the same author) doesn't allow for the caption being placed onto the box's sides.
Using @GonzaloMedina's code (here), and @egreg's suggestion, the desired code is the following:
It produces the following PDF (cropped here):