This task was listed as a Google Summer of Code project idea, but it has been completed.

IRC, freenode, #hurd, 2011-06-01:

<gnu_srs> Another thing: the lsattr and chattr programs seems to be bogus
  on Hurd. Are they present since they are part of e2fsprogs?
<youpi> I don't think the Hurd has an interface for it
<tschwinge> gnu_srs, youpi: lsattr/chattr are extended attributes, right?
  We do have some patches from years ago for adding some support in glibc,
  but they're not yet integrated.  And also we do have a plan for using
  these instead of our Hurd-specific passive translator information in
  inodes.

If interested in working on this, talk to tschwinge, and see these resources:

• GNU Savannah task #5503, GNU Savannah patch #5126

• http://lists.gnu.org/archive/html/bug-hurd/2006-02/threads.html#00115, http://lists.gnu.org/archive/html/bug-hurd/2006-01/threads.html#00180, http://lists.gnu.org/archive/html/bug-hurd/2006-05/threads.html#00042

• http://www.spinics.net/lists/linux-ext4/msg07260.html, http://www.spinics.net/lists/linux-ext4/msg07259.html, http://www.spinics.net/lists/linux-ext4/msg07261.html

IRC, OFTC, #debian-hurd, 2012-03-18:

<pinotree> notes to self: it seems our ext2 driver comes from linux 2.3.42
  or so, and in linux 2.5.46 ext2/ext3 get xattr and acl support

Test Cases

IRC, freenode, #hurd, 2013-12-06:

<gnu_srs> for fakeroot t.xattr test fails, a known issue?
<braunr> the test must probably be disabled
<braunr> the hurd doesn't support extended attributes currently