diff --git a/crates/buffers/src/lib.rs b/crates/buffers/src/lib.rs
index d6ced8e..b45c891 100644
--- a/crates/buffers/src/lib.rs
+++ b/crates/buffers/src/lib.rs
@@ -1,3 +1,8 @@
+// This crate used for making working with &[u8] or Vec<u8> generic in other parts of librqbit,
+// for nicer display of binary data etc.
+//
+// Not useful outside of librqbit.
+
 use serde::{Deserialize, Deserializer};
 
 use clone_to_owned::CloneToOwned;
diff --git a/crates/clone_to_owned/src/lib.rs b/crates/clone_to_owned/src/lib.rs
index e661cd0..561033f 100644
--- a/crates/clone_to_owned/src/lib.rs
+++ b/crates/clone_to_owned/src/lib.rs
@@ -1,3 +1,11 @@
+// These are helpers for objects that can be borrowed, but can be made owned while changing the type.
+// The difference between e.g. Cow and CloneToOwned, is that we can implement it recursively for owned types.
+//
+// E.g. HashMap<&str, &str> can be converted to HashMap<String, String>.
+//
+// This lets us express types like TorrentMetaInfo<&[u8]> for zero-copy metadata about a bencode buffer in memory,
+// but to have one-line conversion for it into TorrentMetaInfo<Vec<u8>> so that we can store it later somewhere.
+
 use std::collections::HashMap;
 
 pub trait CloneToOwned {
diff --git a/crates/peer_binary_protocol/src/lib.rs b/crates/peer_binary_protocol/src/lib.rs
index 0ba8a57..2535ac7 100644
--- a/crates/peer_binary_protocol/src/lib.rs
+++ b/crates/peer_binary_protocol/src/lib.rs
@@ -1,3 +1,7 @@
+// BitTorrent peer protocol implementation: parsing, serialization etc.
+//
+// Can be used outside of librqbit.
+
 pub mod extended;
 
 use bincode::Options;
diff --git a/crates/sha1w/src/lib.rs b/crates/sha1w/src/lib.rs
index 036bed9..116b6f2 100644
--- a/crates/sha1w/src/lib.rs
+++ b/crates/sha1w/src/lib.rs
@@ -1,8 +1,9 @@
-// Wrapper for sha1 libraries.
-// Sha1 computation is the majority of CPU usage of this library.
-// openssl seems 2-3x faster, so using it for now, but
-// leaving the pure-rust impl here too. Maybe someday make them
-// runtime swappable or enabled with a feature.
+// Wrapper for sha1 libraries to be able to swap them easily,
+// e.g. to measure performance, or change implementations depending on platform.
+//
+// Sha1 computation is the majority of CPU usage of librqbit.
+// openssl is 2-3x faster than rust's sha1.
+// system library is the best choice probably (it's the default anyway).
 
 #[cfg(feature = "sha1-openssl")]
 pub type Sha1 = Sha1Openssl;