Check in the libxslt roll script.

third_party/libxslt/src/libxslt/security.c

 /*
  * security.c: Implementation of the XSLT security framework
  *
  * See Copyright for the status of this software.
  *
  * daniel@veillard.com
  */
 
 #define IN_LIBXSLT
 #include "libxslt.h"
@@ skipping 460 matching lines @@
                              "Network file read for %s refused\n", URL);
                 xmlFreeURI(uri);
                 return(0);
             }
         }
     }
     xmlFreeURI(uri);
     return(1);
 }