Windows builds are created with the help of the opensuse build service http://build.opensuse.org. With the help of wine https://www.winehq.org/ it is possible to run and/or debug umbrello on a linux host.

The documentation of umbrello does not include any related hint. Here are a few hints:

Running umbrello on a linux host:
1. install wine from your distribution
2. download umbrello binary package 
3. a portable package from http://download.kde.org/stable/umbrello/latest/ 
4. unpack the portable package into a folder e.g. ~/umbrello-portable
5. run DBUS_SESSION_BUS_ADDRESS= wine ~/umbrello-portable/bin/umbrello.exe

for opensuse there is an alternative:
1. install wine from your distribution
2. Add package repository for your distribution from  https://build.opensuse.org/repositories/windows:mingw:win32
3.install the following binary packages mingw32-umbrello 
4. run DBUS_SESSION_BUS_ADDRESS= wine /usr/i686-w64-mingw32/sys-root/mingw/bin/umbrello.exe

Debugging umbrello on supported opensuse distroibution

1. install wine from your distribution
2 Add package repository for your distribution from  https://build.opensuse.org/repositories/windows:mingw:win32
3.install the following binary packages mingw32-umbrello mingw32-umbrello-debug mingw32-gdb
4. run DBUS_SESSION_BUS_ADDRESS= wine /usr/i686-w64-mingw32/sys-root/mingw/bin/umbrello.exe
5. open konsole and run
   DBUS_SESSION_BUS_ADDRESS= wine /usr/i686-w64-mingw32/sys-root/mingw/bin/gdbserver.exe --multi  localhost:60000 
6. open another konsole and run
   gdb
7. enter the following commands into gdb
   target extended-remote localhost:60000
   set remote exec-file /usr/i686-w64-mingw32/sys-root/mingw/bin/umbrello.exe
   file /usr/i686-w64-mingw32/sys-root/mingw/bin/umbrello.exe
   b main
   r

To have access to umbrello source code in gdb the mingw32-umbrello source rpm should be installed with e.g. zypper si mingw32-umbrello and unpacked from /usr/src/packages/SOURCES/umbrello... into the requested location.