/etc/apt/apt.conf.d/90libnss-libvirt is in libnss-libvirt 4.0.0-1ubuntu8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | // the nss module (once enabled) will make apt call getdents (LP: #1732030)
apt::sandbox::seccomp::allow { "getdents" };
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