Link: http://trac.tools.ietf.org/wg/httpbis/trac/ticket/107
Origin: http://www.w3.org/mid/5BFAE5F2-0D0C-4C5C-99B4-714BE0E63908@mnot.net
Component: p4-conditional
Last-Modified validation is defined in terms of 'requested variant', whereas ETag validation (If-Match, If-None-Match) seem to go out of their way to say that *any* entity that meets the conditional can be returned, and never mind the selecting headers. I'd be interested in hearing if any implementations actually do that, and unless some are found, I'd suggest we need to tighten up how ETag validation is defined.