/usr/include/clustalo/ is in libclustalo-dev 1.2.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/clustalo/clustal/
/usr/include/clustalo/clustal-omega-config.h
/usr/include/clustalo/clustal-omega.h
/usr/include/clustalo/clustal/hhalign_wrapper.h
/usr/include/clustalo/clustal/ktuple_pair.h
/usr/include/clustalo/clustal/log.h
/usr/include/clustalo/clustal/mbed.h
/usr/include/clustalo/clustal/muscle_tree.h
/usr/include/clustalo/clustal/pair_dist.h
/usr/include/clustalo/clustal/progress.h
/usr/include/clustalo/clustal/seq.h
/usr/include/clustalo/clustal/symmatrix.h
/usr/include/clustalo/clustal/tree.h
/usr/include/clustalo/clustal/util.h
/usr/include/clustalo/clustal/weights.h
/usr/include/clustalo/hhalign/
/usr/include/clustalo/hhalign/general.h
/usr/include/clustalo/hhalign/hhfunc.h
/usr/include/clustalo/squid/
/usr/include/clustalo/squid/gki.h
/usr/include/clustalo/squid/gsi64.h
/usr/include/clustalo/squid/msa.h
/usr/include/clustalo/squid/rk.h
/usr/include/clustalo/squid/sqfuncs.h
/usr/include/clustalo/squid/squid.h
/usr/include/clustalo/squid/sre_random.h
/usr/include/clustalo/squid/ssi.h
/usr/include/clustalo/squid/stockholm.h
/usr/include/clustalo/squid/stopwatch.h
/usr/include/clustalo/squid/vectorops.h
/usr/include/clustalo/squid/version.h