I was recently installing Inkscape with MacPorts through a Mac OSX Leopard Terminal using

"sudo port install inkscape"

And during the search-and-download for dependencies, many of these type of comments were printed:

######################################################################
# As MacPorts does not currently have a post-deactivate hook, 
# you will need to ensure that you manually remove the catalog 
# entry for this port when you uninstall it.  To do so, run 
# "xmlcatmgr remove nextCatalog /opt/local/share/xsl/docbook-xsl/catalog.xml".
######################################################################

Can anyone tell me what this message means? I do not understand what "it" refers to in the phrase 'ensure that you manually remove the catalog entry for this port when you uninstall it'.

Does 'it' refer to a 'this port'? How is a port uninstalled? Mostly: When will I have to manually remove the catalog entry using the provided command?

Also, what is a catalog entry? is that what appears when I type "sudo port search inkscape" ?

I am kind of a MacPorts install n00b. Thanks very much for your time.