This means that any new installs of the LJ code will need to run the following command after doing the initial --init:
cp -a $LJHOME/backup/* $LJHOME
This command will also be needed if you update your LJ code to a version past this changeset. If you don't do this, you won't have things like a homepage or create page.
However, there are also several images which were deleted, so you will also need to do the following:
for img in editinfo hourglass journal pencil scrapbook search userinfo; do svn export http://code.livejournal.org/svn/livejournal/trunk/htdocs/img/$img.gif@14809 $LJHOME/htdocs/img/$img.gif; done