Whence 'gtk2' ?

[chuck gelm <chuck gelm net>]

Howdy, Everyone:

I have found an application that I want to try; Bluefish.
http://bluefish.openoffice.nl/

The documentation for Bluefish says that it requires 'gtk2'.
"It requires gtk2 <http://www.gtk.org/>, libpcre <http://www.pcre.org/> 
and (optional) libaspell <http://aspell.sourceforge.net/> for spell
checking and (also optional) gnome-vfs <http://www.gnome.org/> for 
remote files."

I found this mail list at http://gtk.org, but there seems to
be references only to 'gtk+'.

How do I obtain 'gtk2' ?

Regards,
Chuck Gelm