How to find out from which Slackware package a specific file was installed from

OK. Suppose you need to know from which tgz / txz package the file..., say libIlmImf.so.6, was installed from (in a Slackware Linux system).

 Here it is:

        find /var/log/packages -type f | xargs grep -rl 'libIlmImf.so.6'

 Hope this helps.
 Regards, Rodrigo.