Log Message:
Update to 2.3:
The feature added in this revision is pointer barrier events and releases.
Pointer barriers themselves are an XFixes 5 feature, XI 2.3 adds two
disctinct features to barriers:
* the ability for clients to get notified if pointer movement is restricted
  by a barrier
* the ability for clients to allow a pointer to move through a barrier after
  it was constrained by the barrier

For a more verbose explanation of these features please refer to:
http://who-t.blogspot.com.au/2012/12/whats-new-in-xi-23-pointer-barrier.html