Beaglebone Black kernel sources

I need to build a patched BBB kernel, so have unwillingly started one of
my usual vicious fights with git. The first question to answer is where
the current BBB linux kernel sources are kept - I don’t think github is
the default, though some sources can be found there. It seems to be a
choice between:

Does anyone know which of these is canonical / what the differences are
between them?

Thanks - Will

git:// is
the canonical mainline and
is a stable fork with bug fix patches applied for some time moving

The "official" kernel is at as a set of patches against the
stable fork.

Many thanks: that makes things a lot simpler - Will