/usr/sparc64-linux-gnu/lib/libubsan.so.0 is in libubsan0-sparc64-cross 7.3.0-16ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/sparc64-linux-gnu/lib/libubsan.so.0.0.0
/usr/sparc64-linux-gnu/lib/libubsan.so.0.0.0