https://umbrello.kde.org/
Umbrello UML Modeller is a Unified modelling Language (UML) Diagram program based on KDE technology.
UML allows you-to-create diagrams of software and other systems in a standard format to document or design the structure O F Your programs.
You'll take a look at the screenshots to see Umbrello in action.
Our handbook gives a good introduction to Umbrello and UML modelling.
Umbrello comes with KDE SC, included with every Linux distribution and available through your package manager. See Installation to install Umbrello.
For user support join the Umbrello mailing list.
Install as part of KDE software compilation
Umbrello is part of the KDE software compilation which means it comes with all gnu/linux distributions. You'll be able to install it using your normal software Installation app (Muon, software Centre, Yast etc) or command Li NE Package Manager (yum, Up2date, YaST, Zypper, apt-get, emerge etc).
The package would be called Umbrello, some older distros would package it as kdesdk.
Fedora
At least on Fedora It's also required to install the package oxygen-icon-theme, otherwise Umbrello would not s how any icons.
Linux under Modeling tools Umbrello