At one of the projects I did, we used newlist type=unix to find all .ssh directories. and .ssh/known_hosts files. Unfortunately, zSecure Collect doesn't offer a command to collect (the contents of) these files, and zSecure Audit is limited by the user's privileges.
On other platforms you could add an option to ignore user-specific ssh keys in /etc/ssh/ssh_config
UserKnowHostsFile=/dev/null
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Rob van Hoboken
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