ted@debian:~$ apt-file search libnss3
ia32-libs: /usr/lib32/libnss3.so
ia32-libs: /usr/lib32/libnss3.so.1d
ia32-libs-xulrunner: /usr/lib32/xulrunner/libnss3.so
libnss3: /usr/lib/x86_64-linux-gnu/libnss3.so
libnss3: /usr/share/doc/libnss3/changelog.Debian.gz
libnss3: /usr/share/doc/libnss3/copyright
libnss3: /usr/share/lintian/overrides/libnss3
libnss3-1d: /usr/lib/x86_64-linux-gnu/libnss3.so.1d
libnss3-1d: /usr/share/doc/libnss3-1d/changelog.Debian.gz
libnss3-1d: /usr/share/doc/libnss3-1d/copyright
libnss3-1d: /usr/share/lintian/overrides/libnss3-1d
libnss3-dbg: /usr/share/doc/libnss3-dbg/changelog.Debian.gz
libnss3-dbg: /usr/share/doc/libnss3-dbg/copyright
libnss3-dbg: /usr/share/lintian/overrides/libnss3-dbg
libnss3-dev: /usr/share/doc/libnss3-dev/changelog.Debian.gz
libnss3-dev: /usr/share/doc/libnss3-dev/copyright
libnss3-dev: /usr/share/lintian/overrides/libnss3-dev
libnss3-tools: /usr/share/doc/libnss3-tools/changelog.Debian.gz
libnss3-tools: /usr/share/doc/libnss3-tools/copyright
libnss3-tools: /usr/share/lintian/overrides/libnss3-tools


ted@debian:~$ locate libnss3.so.1d
/usr/lib/libnss3.so.1d
/usr/lib/x86_64-linux-gnu/libnss3.so.1d
/usr/lib32/libnss3.so.1d