How do I find replacements for obsolete packages?

I need: libvtk5-qt4-dev libqt4-dev libqt4-opengl-dev My question on askubuntu: https://askubuntu.com/questions/1406705/how-can-i-fix-unable-to-locate-package-libvtk5-qt4-dev-on-ubuntu-20-04/1406747?noredirect=1#comment2443821_1406747

My boss is like, "Nobody else has had a problem yet."

I tried the following on Ubuntu 20.04 and Ubuntu 18.04, Ubuntu 20.04 and 18.04 on WSL2: sudo add-apt-repository ppa:rock-core/qt4 sudo apt-get install libqt4-declarative qt4-dev-tools qt4-qmake libqtwebkit4 then I search for those packages but I only have libqt4-dev-bin and libqt4-opengl-dev which still leaves libvtk5-qt4-dev