/usr/lib/mysql-testsuite/t/mysqldump-compat.opt is in percona-xtradb-cluster-testsuite-5.5 5.5.34-25.9+dfsg-0ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 | --loose-debug=d,4x_server_emul
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