URI Fragment Identifiers for the text/plain Media Type
draft-wilde-text-fragment-09

It is unclear to me if anything needs to be said about comparison of URI that contain this fragment. 

My understanding of 3986 is that it defined a generic syntax for URI that could be imported into the definitions for specific URI schemes and that all URI types would be subsets of so that an application that did not understand a specific scheme could still parse certain semantics of the URI. However, the detailed specification of the URI of a given scheme would still define what was possible for that scheme. I did not realize that prior to 3986, the fragment was not part of the URI while after 3986 redefined it to be part of the URI and no doubt this is a sign I am confused on some of the history and how the details of how this all works. So please educate me. When I look at ldap 4516, or imap in 2182bis they do not seem to allow a fragment in the URI for theses schemes. I'm not even sure where the ftp URI is defined but in 1738 which looks like it is obsolete, it does not allow a fragment. I am really confused by 2616 which does not seem to allow a fragment in the http URI which, ah, seems either like a bit of a problem or I am very confused about where and how this stuff is all defined. Now, this might all seem irrelevant to this document, but it seems like this is the first document defining a fragment (if there are others, particular for the standard http usage, please point me in the right direction). So given this long ramble, my question is: when implementing ftp or http, what RFCs would tell and implementor that they needed to support fragments in the ftp or http URLs?

So in HTTP, I understand how you fetch the resource, check if it is text/plain and then do the fragment processing if it is. How do you check it was text/plain when using FTP?