/usr/include/xtuple/ is in libxtuplecommon-dev 4.1.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/xtuple/common/
/usr/include/xtuple/common/calendarcontrol.h
/usr/include/xtuple/common/calendargraphicsitem.h
/usr/include/xtuple/common/checkForUpdates.h
/usr/include/xtuple/common/errorReporter.h
/usr/include/xtuple/common/exporthelper.h
/usr/include/xtuple/common/format.h
/usr/include/xtuple/common/graphicstextbuttonitem.h
/usr/include/xtuple/common/gunzip.h
/usr/include/xtuple/common/importhelper.h
/usr/include/xtuple/common/login2.h
/usr/include/xtuple/common/login2Options.h
/usr/include/xtuple/common/metrics.h
/usr/include/xtuple/common/metricsenc.h
/usr/include/xtuple/common/qbase64encode.h
/usr/include/xtuple/common/qmd5.h
/usr/include/xtuple/common/shortcuts.h
/usr/include/xtuple/common/splashconst.h
/usr/include/xtuple/common/storedProcErrorLookup.h
/usr/include/xtuple/common/tarfile.h
/usr/include/xtuple/common/tmp/
/usr/include/xtuple/common/tmp/ui_checkForUpdates.h
/usr/include/xtuple/common/tmp/ui_login2.h
/usr/include/xtuple/common/tmp/ui_login2Options.h
/usr/include/xtuple/common/xbase32.h
/usr/include/xtuple/common/xtsettings.h
/usr/include/xtuple/common/xtupleproductkey.h