This file is indexed.

/etc/gss/mech.d/README is in libgssapi-krb5-2 1.15-1+deb9u1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

1
2
3
Any file places in this directory ending in .conf will be read as a
GSS-API mechanism configuration file, and the mechanisms described in
that file will be dynamically loaded.