/usr/m68k-linux-gnu/lib/libm.so.6 is in libc6-m68k-cross 2.23-0ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/m68k-linux-gnu/lib/libm-2.23.so
/usr/m68k-linux-gnu/lib/libm-2.23.so