/usr/include/guacamole/ is in libguac-dev 0.9.9-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/guacamole/audio-fntypes.h
/usr/include/guacamole/audio-types.h
/usr/include/guacamole/audio.h
/usr/include/guacamole/client-constants.h
/usr/include/guacamole/client-fntypes.h
/usr/include/guacamole/client-types.h
/usr/include/guacamole/client.h
/usr/include/guacamole/error-types.h
/usr/include/guacamole/error.h
/usr/include/guacamole/hash.h
/usr/include/guacamole/instruction-constants.h
/usr/include/guacamole/instruction-types.h
/usr/include/guacamole/instruction.h
/usr/include/guacamole/layer-types.h
/usr/include/guacamole/layer.h
/usr/include/guacamole/object-types.h
/usr/include/guacamole/object.h
/usr/include/guacamole/plugin-constants.h
/usr/include/guacamole/plugin-types.h
/usr/include/guacamole/plugin.h
/usr/include/guacamole/pool-types.h
/usr/include/guacamole/pool.h
/usr/include/guacamole/protocol-types.h
/usr/include/guacamole/protocol.h
/usr/include/guacamole/socket-constants.h
/usr/include/guacamole/socket-fntypes.h
/usr/include/guacamole/socket-types.h
/usr/include/guacamole/socket.h
/usr/include/guacamole/stream-types.h
/usr/include/guacamole/stream.h
/usr/include/guacamole/timestamp-types.h
/usr/include/guacamole/timestamp.h
/usr/include/guacamole/unicode.h