/usr/share/gauche-0.9/0.9.3.3/lib/rfc/ is in gauche 0.9.3.3-8ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/822.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/base64.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/cookie.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/ftp.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/hmac.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/http.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/icmp.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/ip.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/json.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/md5.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/mime.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/quoted-printable.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/sha.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/sha1.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/tls.scm
/usr/share/gauche-0.9/0.9.3.3/lib/rfc/uri.scm