diff --git a/wgpu-hal/src/gles/mod.rs b/wgpu-hal/src/gles/mod.rs
index aeef3418694..aad85106b10 100644
--- a/wgpu-hal/src/gles/mod.rs
+++ b/wgpu-hal/src/gles/mod.rs
@@ -345,6 +345,7 @@ pub struct Buffer {
     raw: Option<glow::Buffer>,
     target: BindTarget,
     size: wgt::BufferAddress,
+    /// Flags to use within calls to [`Device::map_buffer`](crate::Device::map_buffer).
     map_flags: u32,
     data: Option<Arc<MaybeMutex<Vec<u8>>>>,
     offset_of_current_mapping: Arc<MaybeMutex<wgt::BufferAddress>>,