Keys and Keyref - questions about URI syntax

[Robert D Anderson <robander@us.ibm.com>]

Hello,

The keys/keyref topic currently contains this language about characters
that are valid in a DITA key:
A key value consists of one or more space separated key names. Key names
consist of characters that are legal in a URI [RFC 3986] and must not
contain the “{“, “}”, “[“, “]”, “/”, “#”, “?”or space characters. The case
of key names is significant.

I've gotten the following review comment this subject:
The description of what characters can be used is not clear. RFC 3986
should be referenced as a reference, and more detail should be added on
what are the "characters that are legal in a URI". Does this mean URI
reserved characters as they can be used in a URI but only in the context
that the spec defines, or does it mean URI unreserved characters, which
already do not contain some of the characters that the DITA spec excluded?

Could some of those from the keyref workgroup provide better wording? I do
not have a deep familiarity with URIs, so I'm wary of accidentally changing
a meaning that they keyref group agreed on.

For reference - RFC 3986: http://www.ietf.org/rfc/rfc3986.txt

Thanks -

Robert D Anderson
IBM Authoring Tools Development
Chief Architect, DITA Open Toolkit