There are two types of "magic" references in the Perl documentation.
There's a general "handwaving" magic, where the author isn't really interested in describing the (probably bizarrely complicated) mechanism by which a particular process happens. In this case, the magic is knowable, but you probably won't need to know, or even want to ask.
There's also a specific "magic" bitfield attached to every symbol table entry inside. This bitfield records unusual properties about that variable. For example, a tied variable needs to be able to announce that something unsual will happen when it is fetched or stored, so the "tied" "magic" bit is set, and checked by those accessing
So yes, there's "magic" you don't want to know, and there's "magic" that actually means something very specific. Hope that helps.
-- Randal L. Schwartz, Perl hacker