kde-style-qtcurve-qt5 software package provides QtCurve widget style for applications based on Qt 5.x, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install kde-style-qtcurve-qt5
kde-style-qtcurve-qt5 is installed in your system.
Make ensure the kde-style-qtcurve-qt5 package were installed using the commands given below,
$ sudo dpkg-query -l | grep kde-style-qtcurve-qt5 *
You will get with kde-style-qtcurve-qt5 package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | KDE |
| Package | kde-style-qtcurve-qt5 |
| Version | 1.8.18+git20160112-0cd6aae-1 |
| Description | QtCurve widget style for applications based on Qt 5.x |
| Sub Section | KDE |