diff --git a/src/ls.rs b/src/ls.rs
index a6f18f6..dbef1c6 100644
--- a/src/ls.rs
+++ b/src/ls.rs
@@ -3,6 +3,7 @@ use std::path::Path;
 
 use crate::index;
 
+/// Returns an iterator that lists all cache index entries.
 pub fn all<P: AsRef<Path>>(cache: P) -> impl Iterator {
     index::ls(cache.as_ref())
 }