Zune is an open source implementation of MUI which is included in AROS project, it is compatible with MUI3.8 APIs and it has some features which are missed on MUI3.8. In the latest years Zune was ported from AROS to AmigaOS3, and so the only MUI registered features and Zune modern features can be used on OS3 for free.
Zune is even ready to be ported on AmigaOS4.
Many OS4/AROS/OS3 users are interested to have software like OWB-MOS and Ambient on their systems, but these software use new API of MUI4, so the better way to have these software on OS4/AROS/OS3 would be to have MUI4 on these systems. Even many developers waited to have MUI4 API avaible for all Amiga systems.
However MUI author seems not to be interested to do a port of his latest framework version to OS4/AROS/OS3, so only MorphOS users can use these software and only MorphOS developers can use MUI4 for their software.
This new bounty is opened to goal Zune MUI4 compatible. In a similar form Zune can give to their users software like OWB-MorphOS and Ambient with few work on system where Zune is avaiable.
To third parts developers a Zune MUI4 compatible would give an easy way to write their software in a easy portable way between different Amiga flavours without too much work because they could use a only powerful framework API instead to workaround different behaviours of MUI3.8/MUI3.9/Zune.