how does git svn work

Hi,

is there a document explaining the internals of GIT-SVN? I'd like to know, which SVN commands are executed in the background and how git-svn recognizes branch creation in SVN.

In particular I want to follow the repository at: http://pubsvn.ez.no/nextgen/

The layout is like
/trunk
/stable
  |- 4.0
  |- 3.9
  |- 3.8
  ...
/releases
  |- 4.0
  |- 4.0r1
  |- 3.9
  |- 3.9r1
  |- 3.9r2

I do not know, whether git-svn can create branches automatically for each directory under /stable and one main branch for trunk or whether I need to create one svn-remote definition for every svn directory I want to track.

Best regards,