/usr/mips64-linux-gnuabi64/libo32/libthread_db.so.1 is in libc6-mips32-mips64-cross 2.23-0ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/mips64-linux-gnuabi64/libo32/libthread_db-1.0.so