Qt Creator doesn't recognize Qt installation directory

PLEASE NOTE: I just found that I'm running version 4.13 beta 1.

I just built Qt 5.15 and Qt Creator (on Mac OS). On first launch, Qt Creator prompts you to "Choose Qt installation."

By default (on the Mac), Qt installs to /usr/local/Qt-(version). But neither this nor any subdirectory appears to be recognized as an installation directory by this dialog.

qmake -query returns the following, none of which appears to be acceptable as the "installation" directory. Nor does the directory where qmake resides.

QT_SYSROOT:
QT_INSTALL_PREFIX:/usr/local/Qt-5.15.0
QT_INSTALL_ARCHDATA:/usr/local/Qt-5.15.0
QT_INSTALL_DATA:/usr/local/Qt-5.15.0
QT_INSTALL_DOCS:/usr/local/Qt-5.15.0/doc
QT_INSTALL_HEADERS:/usr/local/Qt-5.15.0/include
QT_INSTALL_LIBS:/usr/local/Qt-5.15.0/lib
QT_INSTALL_LIBEXECS:/usr/local/Qt-5.15.0/libexec
QT_INSTALL_BINS:/usr/local/Qt-5.15.0/bin
QT_INSTALL_TESTS:/usr/local/Qt-5.15.0/tests
QT_INSTALL_PLUGINS:/usr/local/Qt-5.15.0/plugins
QT_INSTALL_IMPORTS:/usr/local/Qt-5.15.0/imports
QT_INSTALL_QML:/usr/local/Qt-5.15.0/qml
QT_INSTALL_TRANSLATIONS:/usr/local/Qt-5.15.0/translations
QT_INSTALL_CONFIGURATION:/Library/Preferences/Qt
QT_INSTALL_EXAMPLES:/usr/local/Qt-5.15.0/examples
QT_INSTALL_DEMOS:/usr/local/Qt-5.15.0/examples
QT_HOST_PREFIX:/usr/local/Qt-5.15.0
QT_HOST_DATA:/usr/local/Qt-5.15.0
QT_HOST_BINS:/usr/local/Qt-5.15.0/bin
QT_HOST_LIBS:/usr/local/Qt-5.15.0/lib
QMAKE_SPEC:macx-clang
QMAKE_XSPEC:macx-clang
QMAKE_VERSION:3.1
QT_VERSION:5.15.0

It would also be nice if this dialog and similar ones gave the user some clue as to what it's looking for. I recall having a similar problem with Qt Creator and trying to identify Android SDK directories.