diff --git a/src/layer.rs b/src/layer.rs
index a63d54ff..ea9a3464 100644
--- a/src/layer.rs
+++ b/src/layer.rs
@@ -237,7 +237,7 @@ impl LayerContents {
     where
         F: FnMut(&Layer) -> bool,
     {
-        self.layers.retain(|layer| layer.name == DEFAULT_LAYER_NAME || predicate(layer))
+        self.layers.retain(|layer| layer.is_default() || predicate(layer));
     }
 
     /// Removes any layers that contain no glyphs
@@ -452,6 +452,14 @@ impl Layer {
         self.glyphs.is_empty()
     }
 
+    /// Returns `true` if this layer is the default layer.
+    ///
+    /// The default layer can have any name, but always uses the "glyphs"
+    /// directory.
+    pub fn is_default(&self) -> bool {
+        self.path == Path::new(DEFAULT_GLYPHS_DIRNAME)
+    }
+
     /// Returns the name of the layer.
     ///
     /// This can only be mutated through the [`LayerContents`].
@@ -904,12 +912,13 @@ mod tests {
             ],
             ..Default::default()
         };
+        layers.rename_layer("public.default", "foreground", false).unwrap();
 
         layers.retain(|l| l.name().starts_with("fizz"));
 
         assert_eq!(layers.len(), 3, "wrong number of layers deleted");
         let names = layers.iter().map(|l| l.name().as_str()).collect::<Vec<_>>();
-        assert_eq!(names.as_slice(), &[DEFAULT_LAYER_NAME, "fizz", "fizzbuzz"]);
+        assert_eq!(names.as_slice(), &["foreground", "fizz", "fizzbuzz"]);
     }
 
     #[test]