Add an entry in glossary for UVIP

content/en/docs/reference/glossary/mixed-version-proxy.md

@@ -0,0 +1,21 @@
+---
+title: Mixed Version Proxy (MVP)
+id: mvp
+date: 2023-07-24
+full_link: /docs/concepts/architecture/mixed-version-proxy#Enabling-the-Mixed-Version-Proxy
+short_description: >
+  Feature that lets a kube-apiserver proxy a resource request to a different peer API server. 
+aka: ["MVP"]
+tags:
+- architecture
+---
+Feature to let a kube-apiserver proxy a resource request to a different peer API server.
+
+<!--more-->
+
+When a cluster has multiple API servers running different versions of Kubernetes, this 
+feature enables resource requests to be served by the correct API server.
+
+MVP is disabled by default and can be activated by enabling
+the feature gate named `UnknownVersionInteroperabilityProxy` when 
+{{< glossary_tooltip text="API Server" term_id="kube-apiserver" >}} is started.