[PATCH v3 4/4] Documentation: document foreign idents

[Marcus Comstedt <marcus@mc.pp.se>]

Add a short paragraph to the "ident" documentation about the
semantics and intended use of foreign idents.

Signed-off-by: Marcus Comstedt <marcus@mc.pp.se>
Signed-off-by: Henrik Grubbström <grubba@grubba.org>
---
 Documentation/gitattributes.txt |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index e5a27d8..9af1d6f 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -272,6 +272,13 @@ sign `$` upon checkout.  Any byte sequence that begins with
 `$Id:` and ends with `$` in the worktree file is replaced
 with `$Id$` upon check-in.
 
+When converting a repository from a different version control
+system, it can be useful to create blobs which contain expanded
+`$Id$` tags.  Git will recognize such "foreign idents" if they
+contain at least one space within the payload.  A foreign ident
+will be replaced by `$Id$` upon check-in, but is left unaltered
+upon checkout.
+
 
 `filter`
 ^^^^^^^^
-- 
1.7.2