According to http://www.ietf.org/rfc/rfc2732.txt, the use of '[' and ']' within a IPv6 URI is valid. However, EMC Documentum escapes them to %5B and %5D. This behavior does not follow RFC 2732.
An example IPv6 URL is http://[2001:1890:110b:661f:65d4:c37c:1d82:f2e6]:8080.