How does the views module affect taxonomy term pages?

The views module provides a way to redefine how the taxonomy
term  
pages appear.  How is this accomplished without patching the
taxonomy  
module?  Is there a hook I don't know about, or does the
views module  
simply override the $menu entry?  I have looked briefly
through the  
code in both modules, but the interaction is  not clear to
me.  Both  
modules are complex.

However it works, it's a neat trick.  I would like to
borrow it.

Nic Ivy