LLVM PPA: Script source availability

[Whisperity]

Dear PPA Team,

I would like to ask where the scripts for the Debian packages
maintained by the Foundation are available for contribution? I was not
able to find them in the official LLVM mono-repository.
My main contribution idea would be setting up automatic calls to
`update-alternatives` so installing, e.g. Clang, would register the
necessary binaries into the alternatives system automatically, so it
is easy for users to set `clang` to be a specific version -- something
which is currently missing from the Debian packages, and setting up
the paths for **all** the binaries is non-trivial automatically from a
client's point of view.

Regards,
Whisperity.