[isabelle-dev] Are sources available?

[Yuri]

The website says "Isabelle is distributed for free under a conglomerate 
of open-source licenses, but the main code-base is subject to BSD-style 
regulations." (https://www.cl.cam.ac.uk/research/hvg/Isabelle/)

This seems to mean that sources should be available, but there is no 
sources link. The "Installation" page only lists binary downloads.


I tried to create a FreeBSD port for isabelle, but can't do this without 
the sources.


Yuri