Add a comment to the top of the file explaining why the file is here.
diff --git a/Doc/lib/mimelib.tex b/Doc/lib/mimelib.tex
index c0e01eb..635bcd9 100644
--- a/Doc/lib/mimelib.tex
+++ b/Doc/lib/mimelib.tex
@@ -1,3 +1,10 @@
+% This document is largely a stub used to allow the email package docs
+% to be formatted separately from the rest of the Python
+% documentation. This allows the documentation to be released
+% independently of the rest of Python since the email package is being
+% maintained for multiple Python versions, and on an accelerated
+% schedule.
+
\documentclass{howto}
\title{email Package Reference}