Why Does bind Have So Many Dependencies

I got notice the bind 9.16 was going EOL and to upgrade to 9.18.

When I built from source, I saw this very long list of other stuff
that got build.  X libs?  doxygen?   Why  all this:

[root] ozzie  /ports/dns/bind918>make clean
===>  Cleaning for fstrm-0.6.1_1
===>  Cleaning for protobuf-c-1.4.1_2
===>  Cleaning for doxygen-1.9.6_1,2
===>  Cleaning for graphviz-9.0.0_3
===>  Cleaning for groff-1.23.0_3
===>  Cleaning for gsfonts-8.11_8
===>  Cleaning for psutils-1.17_6
===>  Cleaning for uchardet-0.0.8_1
===>  Cleaning for ghostscript10-10.03.0_1
===>  Cleaning for jbig2dec-0.20_1
===>  Cleaning for openjpeg-2.5.2
===>  Cleaning for cups-2.4.7_2
===>  Cleaning for avahi-app-0.8_2
===>  Cleaning for intltool-0.51.0_2
===>  Cleaning for p5-XML-Parser-2.47
===>  Cleaning for libdaemon-0.14_1
===>  Cleaning for dbus-glib-0.112_1
===>  Cleaning for gnome_subr-1.0
===>  Cleaning for gnutls-3.7.10_2
===>  Cleaning for nettle-3.9.1
===>  Cleaning for libtasn1-4.19.0_1
===>  Cleaning for gtk-doc-1.33.2_2
===>  Cleaning for itstool-2.0.7_1
===>  Cleaning for yelp-tools-42.0
===>  Cleaning for yelp-xsl-42.0
===>  Cleaning for p11-kit-0.25.3_1
===>  Cleaning for bash-completion-2.12.0,2
===>  Cleaning for poppler-data-0.4.12
===>  Cleaning for urw-base35-fonts-20200910
===>  Cleaning for libXaw-1.0.14_1,2
===>  Cleaning for libXpm-3.5.17_1
===>  Cleaning for libltdl-2.4.7
===>  Cleaning for webp-1.3.2_1
===>  Cleaning for libgd-2.3.3_9,1
===>  Cleaning for protobuf-24.4,1
===>  Cleaning for abseil-20230125.3
===>  Cleaning for bind918-9.18.24