docs: URI schemes (#958)

protocol/xftp-uri-request.txt

@@ -0,0 +1,16 @@
+Scheme name: xftp
+
+Status: Provisional
+
+Applications/protocols that use this scheme name:
+This scheme is used for URIs of XFTP (SimpleX File Transfer Protocol) servers,
+a client-server protocol for asynchronous file transfer via relays,
+preserving file meta-data (including size and name) and content privacy.
+
+Contact: Evgeny Poberezkin <ep@simplex.chat>
+
+Change controller: Evgeny Poberezkin <ep@simplex.chat>
+
+References:
+The syntax for server URIs in the provisional specification for SimpleX File Transfer Protocol:
+https://github.com/simplex-chat/simplexmq/blob/master/rfcs/2022-12-26-simplex-file-transfer.md#server-address-syntax

protocol/xrcp-uri-request.txt

@@ -0,0 +1,15 @@
+Scheme name: xrcp
+
+Status: Provisional
+
+Applications/protocols that use this scheme name:
+This scheme is used for URIs of controller sessions via SimpleX Remote Control protocol (XRCP),
+a protocol for remote access and management of hosts via insecure network.
+
+Contact: Evgeny Poberezkin <ep@simplex.chat>
+
+Change controller: Evgeny Poberezkin <ep@simplex.chat>
+
+References:
+The syntax for server URIs in the provisional specification for SimpleX File Transfer Protocol:
+https://github.com/simplex-chat/simplexmq/blob/master/rfcs/2023-10-25-remote-control.md#session-invitation

rfcs/2022-12-26-simplex-file-transfer.md

@@ -149,6 +149,19 @@ parts:
 
 This file description is sent to all recipients via normal messages, split to 15780 byte chunks if needed.
 
+### Server address syntax
+
+The server address is a URI with the following format:
+
+```abnf
+xftpServerURI = %s"xftp://" xftpServer
+xftpServer = serverIdentity "@" srvHost [":" port]
+srvHost = <hostname> ; RFC1123, RFC5891
+port = 1*DIGIT
+serverIdentity = base64url
+base64url = <base64url encoded binary> ; RFC4648, section 5
+```
+
 ### Receiving file
 
 Having received the description, the recipient will: