/usr/share/syslinux/themes/ is in syslinux-themes-debian-squeeze 10-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/syslinux/themes/debian-squeeze/
/usr/share/syslinux/themes/debian-squeeze/extlinux/
/usr/share/syslinux/themes/debian-squeeze/extlinux/config.c32
/usr/share/syslinux/themes/debian-squeeze/extlinux/hdt.c32
/usr/share/syslinux/themes/debian-squeeze/extlinux/memtest.bin
/usr/share/syslinux/themes/debian-squeeze/extlinux/menu.cfg
/usr/share/syslinux/themes/debian-squeeze/extlinux/other.cfg
/usr/share/syslinux/themes/debian-squeeze/extlinux/reboot.c32
/usr/share/syslinux/themes/debian-squeeze/extlinux/rosh.c32
/usr/share/syslinux/themes/debian-squeeze/extlinux/splash.png
/usr/share/syslinux/themes/debian-squeeze/extlinux/stdmenu.cfg
/usr/share/syslinux/themes/debian-squeeze/extlinux/theme.cfg
/usr/share/syslinux/themes/debian-squeeze/extlinux/vesamenu.c32
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/config.c32
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/hdt.c32
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/isolinux.bin
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/isolinux.cfg
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/live.cfg
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/memtest.bin
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/menu.cfg
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/other.cfg
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/reboot.c32
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/rosh.c32
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/splash.png
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/stdmenu.cfg
/usr/share/syslinux/themes/debian-squeeze/isolinux-live/vesamenu.c32
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/config.c32
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/hdt.c32
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/isolinux.bin
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/isolinux.cfg
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/live.cfg
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/memtest.bin
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/menu.cfg
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/other.cfg
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/reboot.c32
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/rosh.c32
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/splash.png
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/stdmenu.cfg
/usr/share/syslinux/themes/debian-squeeze/syslinux-live/vesamenu.c32