diff --git a/bitcoin/Cargo.toml b/bitcoin/Cargo.toml
index 0b5f47fe..ceb793c9 100644
--- a/bitcoin/Cargo.toml
+++ b/bitcoin/Cargo.toml
@@ -42,6 +42,8 @@ hex_lit = "0.1.1"
 
 base64 = { version = "0.13.0", optional = true }
 bitcoinconsensus = { version = "0.20.2-0.5.0", default-features = false, optional = true }
+
+# There is no reason to use this dependency directly, it is activated by the "no-std" feature.
 core2 = { version = "0.3.2", default-features = false, features = ["alloc"], optional = true }
 # Do NOT use this as a feature! Use the `serde` feature instead.
 actual-serde = { package = "serde", version = "1.0.103", default-features = false, features = [ "derive", "alloc" ], optional = true }