diff --git a/src/comp/metadata/creader.rs b/src/comp/metadata/creader.rs
index e46b2585b1e..c5a17bebae4 100644
--- a/src/comp/metadata/creader.rs
+++ b/src/comp/metadata/creader.rs
@@ -1,6 +1,5 @@
+// Extracting metadata from crate files
 
-
-// -*- rust -*-
 import driver::session;
 import front::ast;
 import lib::llvm::False;
diff --git a/src/comp/metadata/cwriter.rs b/src/comp/metadata/cwriter.rs
index bd3d691ee39..eedf973fdbb 100644
--- a/src/comp/metadata/cwriter.rs
+++ b/src/comp/metadata/cwriter.rs
@@ -1,3 +1,4 @@
+// Writing metadata into crate files
 
 import std::str;
 import middle::trans;
diff --git a/src/comp/metadata/decoder.rs b/src/comp/metadata/decoder.rs
index 9504cab11e8..aee4a48cdaf 100644
--- a/src/comp/metadata/decoder.rs
+++ b/src/comp/metadata/decoder.rs
@@ -1,3 +1,5 @@
+// Metadata decoding
+
 import std::ebml;
 import std::option;
 import std::vec;
diff --git a/src/comp/metadata/defs.rs b/src/comp/metadata/defs.rs
index 1584ee46c5b..9ce5a7947f5 100644
--- a/src/comp/metadata/defs.rs
+++ b/src/comp/metadata/defs.rs
@@ -1,3 +1,4 @@
+// EBML tag definitions shared by the encoder and decoder
 
 const uint tag_paths = 0x01u;
 
diff --git a/src/comp/metadata/encoder.rs b/src/comp/metadata/encoder.rs
index 88804a344c3..592a248d412 100644
--- a/src/comp/metadata/encoder.rs
+++ b/src/comp/metadata/encoder.rs
@@ -1,3 +1,5 @@
+// Metadata encoding
+
 import std::str;
 import std::vec;
 import std::uint;
diff --git a/src/comp/metadata/tydecode.rs b/src/comp/metadata/tydecode.rs
index 2627459e297..300fc2c6975 100644
--- a/src/comp/metadata/tydecode.rs
+++ b/src/comp/metadata/tydecode.rs
@@ -1,4 +1,5 @@
 // Type decoding
+
 import std::str;
 import std::vec;
 import std::uint;