Comment by ur-whale

Not sure HN is the best forum for debugging such issues, but nevertheless, here goes:

    # lsb_release -a
    Ubuntu 20.04.5 LTS

    # qmake --version
    QMake version 3.1
    Using Qt version 5.12.8 in /usr/lib/x86_64-linux-gnu

    # qmake-qt5 --version
    qmake-qt5: command not found

    # apt-file search qmake-qt5
    qt5-qmake-bin: /usr/share/man/man1/qmake-qt5.1.gz

    # /usr/lib/qt5/bin/qmake --version
    QMake version 3.1
    Using Qt version 5.12.8 in /usr/lib/x86_64-linux-gnu

I don't recall doing anything special to install Qt on my box, likely something along the lines of:

    # apt-get install qt5-default

So in all likelihood, I have the standard Qt5 that comes with Ubuntu 20.04.5, still a somewhat popular and widely used Ubuntu version.

Hope this helps.