Make changes suggested by Mark, make this pass sanity
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 758ba24..8b7ec50 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -764,6 +764,7 @@
 doc/PROTOCOL-WEB.md \
 doc/binary-logging.md \
 doc/c-style-guide.md \
+doc/combiner-explainer.md \
 doc/command_line_tool.md \
 doc/compression.md \
 doc/compression_cookbook.md \