That doesn't seem to work...
Here's my .git/config file before the first fetch:
[svn-remote "svn"]
useSvnsyncProps = 1
ignore-paths = ^[^/]+/(?:cvs2svn|projects|svnadmin|user|vendor.*)
url = file:///home/marcnarc/Code/FreeBSD-all-mirror/base
fetch = head:refs/remotes/trunk
branches = stable/*:refs/remotes/stable/*
branches = releng/*:refs/remotes/releng/*
tags = release/*:refs/remotes/tags/*(Shouldn't that fetch line be head:refs/remots/head, since there's nothing called "trunk" in the svn repo? I used git-svn init --trunk=head ...)
With this, git-svn seems to be (mostly) ignoring the branches in stable/. I've run the first fetch past the point where the first stable/ branch is created ("stable/2.0.5"), but in the repository (while the fetch command is still going, BTW, currently somewhere around commit 15,000), I get: $ git branch -a
remotes/releng/2.0.5
remotes/releng/ALPHA_2_0
remotes/releng/BETA_2_0
remotes/tags/2.0
remotes/tags/2.0.5
remotes/tags/2.1.0
remotes/tags/2.1.0@12369
remotes/trunk
At this point, git-svn has passed the commit that created the stable/2.0.5 branch (8869). Mind you, nothing was ever committed to that branch, so it's basically a tag. However, remotes/tags/2.0.5 is at svn commit 9201, which is the correct for the releases/2.0.5 tag. remotes/tags/2.1.0 is also correct for the tagging of the 2.1.0 release.
git-svn has also passed the commit that created the stable/2.1 branch (9211), as well as later commits that only apply to that branch. AFAICT, remotes/tags/2.1.0@12369 (which is not an actual tag or branch in the svn repo) is the stable/2.1 branch up to commit 12369, but there have been later commits to stable/2.1 since then that git-svn has seen. Those later commits don't seem to be in the git repository at all.
The releng/* branches look fine, though.