Yep, the Sybase Open Watcom Public License. The OSI considers this license open source [1], the FSF and major distros don't [2], including Fedora [3] and Debian [4].
It is notably used by the Open Watcom C compiler, which is used to compile VirtualBox's BIOS. Which is the reason why you won't find VirtualBox in most distros, including Debian.
The reason the FSF and major distros don't consider it free is that there are cases where you can't use it privately without releasing your modifications. The license doesn't pass Debian's Desert Island test [5]:
> Imagine a castaway on a desert island with a solar-powered computer. This would make it impossible to fulfill any requirement to make changes publicly available or to send patches to some particular place. This holds even if such requirements are only upon request, as the castaway might be able to receive messages but be unable to send them. To be free, software must be modifiable by this unfortunate castaway, who must also be able to legally share modifications with friends on the island.
I don't have an example of a license that the FSF / GNU project considers free and that the OSI doesn't consider open source.
> Oops... it looks like OSI smoked something especially bad this time, I'm afraid. This license looks like someone took his time to collect every single problematic clause.
It is notably used by the Open Watcom C compiler, which is used to compile VirtualBox's BIOS. Which is the reason why you won't find VirtualBox in most distros, including Debian.
The reason the FSF and major distros don't consider it free is that there are cases where you can't use it privately without releasing your modifications. The license doesn't pass Debian's Desert Island test [5]:
> Imagine a castaway on a desert island with a solar-powered computer. This would make it impossible to fulfill any requirement to make changes publicly available or to send patches to some particular place. This holds even if such requirements are only upon request, as the castaway might be able to receive messages but be unable to send them. To be free, software must be modifiable by this unfortunate castaway, who must also be able to legally share modifications with friends on the island.
I don't have an example of a license that the FSF / GNU project considers free and that the OSI doesn't consider open source.
[1] https://directory.fsf.org/wiki/License:Watcom-1.0
[2] https://opensource.org/license/sybase-php
[3] https://en.wikipedia.org/wiki/Sybase_Open_Watcom_Public_Lice...
[4] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=376431
> Oops... it looks like OSI smoked something especially bad this time, I'm afraid. This license looks like someone took his time to collect every single problematic clause.
[5] https://people.debian.org/~bap/dfsg-faq.html#desert_island