Step 1: RTFM

[Klingenstein, Nate]

> You do, but it wasn't obvious it was either in one or the other, not both.  That's
> obvious if you're interested in the version control, but less so if you just want a
> checkout.  I had presumed the migration of big stuff was done.

(and yes, this is in bold on the source code access page and I obviously see it now, but it wasn't mentioned e.g. in

https://wiki.shibboleth.net/confluence/display/IDP30/DevelopmentEnvironmentSetup

and there's a lot of documentation that reads as if Git is it, which is obviously the goal)

Once a repository has been migrated to Git, the version previously available through Subversion will no longer be available.