/etc/logcheck/ignore.d.server/cyrus is in logcheck-database 1.3.17.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | ^\w{3} [ :0-9]{11} [._[:alnum:]-]+ (cyrus/)?notifyd\[[0-9]+\]: do_notify using method '(null|log|zephyr)'$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ cyrus/imapd\[[0-9]+\]: SQUAT failed( to open index file)?$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ cyrus/imapd\[[0-9]+\]: SQUAT returned [0-9]+ messages$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ cyrus/lmtpd\[[0-9]+\]: DBERROR db3: [12] lockers$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ cyrus/notifyd\[[0-9]+\]: MAIL, , [^[:space:]]+, [^[:space:]]+, \"[ [:alnum:][:punct:]]+\"$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ cyrus/squatter\[[0-9]+\]: (skipping|indexing) mailbox [[:alpha:]^\.]+\.\.\.$
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