1diff --git a/include/libxml/tree.h b/include/libxml/tree.h
2index e5a8fb709471f..7819d5819b427 100644
3--- a/include/libxml/tree.h
4+++ b/include/libxml/tree.h
5@@ -454,6 +454,7 @@ struct _xmlAttr {
6 xmlAttributeType atype; /* the attribute type if validating */
7 void *psvi; /* for type/PSVI information */
8 struct _xmlID *id; /* the ID struct */
9+ unsigned int extra; /* extra data for XPath/XSLT */
10 };
11
12 /**
13@@ -592,6 +593,7 @@ struct _xmlDoc {
14 document */
15 int properties; /* set of xmlDocProperties for this document
16 set at the end of parsing */
17+ unsigned int extra; /* extra data for XPath/XSLT */
18 };
19
20