/usr/lib/Wt/test/ is in witty-examples 3.1.10-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/Wt/test/CMakeLists.txt
/usr/lib/Wt/test/CMakeLists.txt.orig
/usr/lib/Wt/test/chart/
/usr/lib/Wt/test/chart/WChartTest.C
/usr/lib/Wt/test/color/
/usr/lib/Wt/test/color/WColorTest.C
/usr/lib/Wt/test/dbo/
/usr/lib/Wt/test/dbo/DboTest.C
/usr/lib/Wt/test/dbo/DboTest2.C
/usr/lib/Wt/test/length/
/usr/lib/Wt/test/length/WLengthTest.C
/usr/lib/Wt/test/models/
/usr/lib/Wt/test/models/WBatchEditProxyModelTest.C
/usr/lib/Wt/test/paintdevice/
/usr/lib/Wt/test/paintdevice/WRasterTest.C
/usr/lib/Wt/test/paintdevice/WSvgTest.C
/usr/lib/Wt/test/private/
/usr/lib/Wt/test/private/CExpressionParserTest.C
/usr/lib/Wt/test/private/DboImplTest.C
/usr/lib/Wt/test/private/HttpTest.C
/usr/lib/Wt/test/private/I18n.C
/usr/lib/Wt/test/private/i18n/
/usr/lib/Wt/test/private/i18n/plain.xml
/usr/lib/Wt/test/private/i18n/plain_nl.xml
/usr/lib/Wt/test/private/i18n/plural.xml
/usr/lib/Wt/test/private/i18n/plural_err_1.xml
/usr/lib/Wt/test/private/i18n/plural_err_2.xml
/usr/lib/Wt/test/private/i18n/plural_err_3.xml
/usr/lib/Wt/test/private/i18n/plural_err_4.xml
/usr/lib/Wt/test/private/i18n/plural_err_5.xml
/usr/lib/Wt/test/private/i18n/plural_findcase_err1.xml
/usr/lib/Wt/test/private/i18n/plural_findcase_err2.xml
/usr/lib/Wt/test/private/i18n/plural_pl.xml
/usr/lib/Wt/test/test.C
/usr/lib/Wt/test/utf8/
/usr/lib/Wt/test/utf8/Utf8Test.C
/usr/lib/Wt/test/utf8/XmlTest.C
/usr/lib/Wt/test/wdatetime/
/usr/lib/Wt/test/wdatetime/WDateTimeTest.C