# HG changeset patch
# User Gregory Szorc <gregory.szorc@gmail.com>
# Date 2017-07-01 17:36:03
# Node ID cd1c275c94825ca67188075b0de0a61a32d54068
# Parent  abd7dedbaa36a29192e713e71338855defe97051

sparse: expand module docstring

Clarify lack of BC guarantees. And say a bit more about the extension.

diff --git a/hgext/sparse.py b/hgext/sparse.py
--- a/hgext/sparse.py
+++ b/hgext/sparse.py
@@ -6,6 +6,17 @@
 # GNU General Public License version 2 or any later version.
 
 """allow sparse checkouts of the working directory (EXPERIMENTAL)
+
+(This extension is not yet protected by backwards compatibility
+guarantees. Any aspect may break in future releases until this
+notice is removed.)
+
+This extension allows the working directory to only consist of a
+subset of files for the revision. This allows specific files or
+directories to be explicitly included or excluded. Many repository
+operations have performance proportional to the number of files in
+the working directory. So only realizing a subset of files in the
+working directory can improve performance.
 """
 
 from __future__ import absolute_import