/usr/include/ is in libunittest++-dev 1.4.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/unittest++/
/usr/include/unittest++/CurrentTest.h
/usr/include/unittest++/Test.h
/usr/include/unittest++/TestReporter.h
/usr/include/unittest++/TestSuite.h
/usr/include/unittest++/DeferredTestResult.h
/usr/include/unittest++/TestDetails.h
/usr/include/unittest++/TestReporterStdout.h
/usr/include/unittest++/TestList.h
/usr/include/unittest++/AssertException.h
/usr/include/unittest++/ReportAssert.h
/usr/include/unittest++/CheckMacros.h
/usr/include/unittest++/MemoryOutStream.h
/usr/include/unittest++/Config.h
/usr/include/unittest++/TestRunner.h
/usr/include/unittest++/ExecuteTest.h
/usr/include/unittest++/UnitTest++.h
/usr/include/unittest++/TestMacros.h
/usr/include/unittest++/XmlTestReporter.h
/usr/include/unittest++/DeferredTestReporter.h
/usr/include/unittest++/TimeConstraint.h
/usr/include/unittest++/TimeHelpers.h
/usr/include/unittest++/Checks.h
/usr/include/unittest++/Posix/
/usr/include/unittest++/Posix/SignalTranslator.h
/usr/include/unittest++/Posix/TimeHelpers.h
/usr/include/unittest++/TestResults.h