Q: How can I install sid (unstable) with DebianInstaller?

[Teodor MICU <mteodor@gmail.com>]

I was trying to install "stable" using debian-installer from testing
for supported network drivers. Sadly, this function was removed at
some point.

"Start the installation in expert mode. After selecting a mirror you
will be asked which distribution to install: stable, testing or
unstable. We recommend using a daily build of the installer to install
testing or unstable."

I hope this function will be restored into debian-installer.

Cheers