Content-Location: path separator characters

Section 3.3 Disposition Parameter: 'Filename' says

"""
When the value contains path separator characters, all but the last segment SHOULD be ignored. This prevents unintentional overwriting of well-known file system location (such as "/etc//passwd").
"""

However, "path separator characters" is not defined; should this be platform-specific, or should we nominate the characters in question? Either way, it needs to be more explicit.

Nit: the end of the quoted sentence above should be "... well-known file system locations ... "

--
Mark Nottingham   http://www.mnot.net/