The tag is present in Lintian version 2.104.328. That is the most recent version we know about.
This package appears to modify
/etc/ld.so.conf and does not
appear to be part of libc. Packages installing shared libraries in
non-standard locations were previously permitted to modify
/etc/ld.so.conf to add the non-standard path, but this permission was
removed in Policy 3.8.3.
Packages containing shared libraries should either install them into
/usr/lib or should require binaries built against them to set
RPATH to find the library at run-time. Installing libraries in a
different directory and modifying the run-time linker path is equivalent
to installing them into
/usr/lib except now conflicting library
packages may cause random segfaults and difficult-to-debug problems
instead of conflicts in the package manager.