The tag is present in Lintian version 2.104.328. That is the most recent version we know about.
The package is architecture-dependent, ships a shared library in
a public library search path and is marked
foreign. Typically, shared libraries are marked
same when possible. Sometimes, private shared libraries are put
into the public library search path to accommodate programs in the
same package, but this package does not contain any programs.
Please remove the
Multi-Arch: foreign stanza.