/usr/lib/x86_64-linux-gnu/singularity/libsingularity-runtime.so.1 is in singularity-container 2.4.2-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/singularity/libsingularity-runtime.so.1.0.0