more links to XiK and JiK

README.md

@@ -215,6 +215,16 @@ foo bar=true "baz" quux=false 1 2 3
 1. Ease of de/serialization
 1. Ease of implementation
 
+## Compatibility with JSON and XML
+
+There are two specifications for writing KDL that can be losslessly translated
+between it and JSON or XML. These specifications define a stricter _subset_ of
+KDL that, even if not entirely idiomatic, is still valid and fits into the
+data models of the other two languages:
+
+* [JSON in KDL](JSON-IN-KDL.md)
+* [XML in KDL](XML-IN-KDL.md)
+
 ## FAQ
 
 #### How do you pronounce KDL?
@@ -279,7 +289,9 @@ forgiving syntax without being so flexible as to allow certain classes of
 unfortunate mistakes. It also has much more flexibility around how to
 represent data.
 
-If you need to interoperate with a service that consumes or emits JSON, or for some other reason have need to write "JSON in KDL", [we have JiK, an official microsyntax for losslessly encoding JSON](JSON-IN-KDL.md).
+If you need to interoperate with a service that consumes or emits JSON, or for
+some other reason have need to write "JSON in KDL", [we have JiK, an official
+microsyntax for losslessly encoding JSON](JSON-IN-KDL.md).
 
 #### What about TOML?
 
@@ -308,6 +320,10 @@ Finally, KDL is **not** a markup language. XML or HTML do a much better job of
 useful for templating engines that want to be more strict about text
 fragments.
 
+If you need to interoperate with a service that consumes or emits XML, or for
+some other reason have need to write "XML in KDL", [we have XiK, an official
+microsyntax for losslessly encoding XML](XML-IN-KDL.md).
+
 ## License
 
 <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-sa/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution-ShareAlike 4.0 International License</a>.