diff --git a/zarr/convenience.py b/zarr/convenience.py
index 27b0655baa..1bb99c92e4 100644
--- a/zarr/convenience.py
+++ b/zarr/convenience.py
@@ -1120,7 +1120,6 @@ def is_zarr_key(key):
         return (key.endswith('.zarray') or key.endswith('.zgroup') or
                 key.endswith('.zattrs'))
 
-#    out = {key: store[key].decode() for key in store if is_zarr_key(key)}
     out = {
         'zarr_consolidated_format': 1,
         'metadata': {
diff --git a/zarr/meta.py b/zarr/meta.py
index bef53c2917..9ce580eff2 100644
--- a/zarr/meta.py
+++ b/zarr/meta.py
@@ -34,13 +34,21 @@ def json_dumps(o):
 
 
 def parse_metadata(s):
+
+    # Here we allow that a store may return an already-parsed metadata object,
+    # or a string of JSON that we will parse here. We allow for an already-parsed
+    # object to accommodate a consolidated metadata store, where all the metadata for
+    # all groups and arrays will already have been parsed from JSON.
+
     if isinstance(s, Mapping):
         # assume metadata has already been parsed into a mapping object
         meta = s
+
     else:
         # assume metadata needs to be parsed as JSON
         s = ensure_str(s)
         meta = json.loads(s)
+
     return meta