diff --git a/libnczarr/zformat2.c b/libnczarr/zformat2.c
index 158be08e95..e27148031c 100644
--- a/libnczarr/zformat2.c
+++ b/libnczarr/zformat2.c
@@ -734,11 +734,13 @@ ZF2_upload_grp(NC_FILE_INFO_T* file, NC_GRP_INFO_T* grp, struct ZOBJ* zobj)
     if((stat=NCZ_uploadjson(zinfo->map,key,zobj->jobj))) goto done;
     nullfree(key); key = NULL;
 
-    /* build ZATTRS path */
-    if((stat = nczm_concat(fullpath,Z2ATTRS,&key))) goto done;
-    /* Write to map */
-    if((stat=NCZ_uploadjson(zinfo->map,key,zobj->jatts))) goto done;
-    nullfree(key); key = NULL;
+    if(zobj->jatts != NULL) {
+	/* build ZATTRS path */
+	if((stat = nczm_concat(fullpath,Z2ATTRS,&key))) goto done;
+	/* Write to map */
+	if((stat=NCZ_uploadjson(zinfo->map,key,zobj->jatts))) goto done;
+	nullfree(key); key = NULL;
+    }
 
 done:
     nullfree(fullpath);
@@ -763,7 +765,7 @@ ZF2_upload_var(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, struct ZOBJ* zobj)
     if((stat=NCZ_uploadjson(zinfo->map,key,zobj->jobj))) goto done;
     nullfree(key); key = NULL;
 
-    if(zobj->jatts) {
+    if(zobj->jatts != NULL) {
 	/* build ZATTRS path */
 	if((stat = nczm_concat(fullpath,Z2ATTRS,&key))) goto done;
 	/* Write to map */
@@ -1271,31 +1273,44 @@ ZF2_searchobjects(NC_FILE_INFO_T* file, NC_GRP_INFO_T* grp, NClist* varnames, NC
     size_t i;
     NCZ_FILE_INFO_T* zfile = (NCZ_FILE_INFO_T*)file->format_file_info;
     char* grpkey = NULL;
+    char* subgrpkey = NULL;
     char* varkey = NULL;
     char* zarray = NULL;
+    char* zgroup = NULL;
     NClist* matches = nclistnew();
 
     /* Compute the key for the grp */
     if((stat = NCZ_grpkey(grp,&grpkey))) goto done;
-    /* Get the map and search group */
-    if((stat = nczmap_list(zfile->map,grpkey,matches))) goto done;
+    if((stat = nczmap_list(zfile->map,grpkey,matches))) goto done; /* Shallow listing */
+    /* Search grp for group-level .zxxx and for var-level .zxxx*/
     for(i=0;i<nclistlength(matches);i++) {
 	const char* name = nclistget(matches,i);
-	if(name[0] == NCZM_DOT) continue; /* zarr/nczarr specific */
-	/* See if name/.zarray exists */
+	if(name[0] == NCZM_DOT) continue; /* current group components */
+	/* See if name is an array by testing for name/.zarray exists */
 	if((stat = nczm_concat(grpkey,name,&varkey))) goto done;
 	if((stat = nczm_concat(varkey,Z2ARRAY,&zarray))) goto done;
-	if((stat = nczmap_exists(zfile->map,zarray)) == NC_NOERR)
+	if((stat = nczmap_exists(zfile->map,zarray)) == NC_NOERR) {
 	    nclistpush(varnames,strdup(name));
+	} else {
+	    /* See if name is a group by testing for name/.zgroup exists */
+	    if((stat = nczm_concat(grpkey,name,&subgrpkey))) goto done;
+	    if((stat = nczm_concat(varkey,Z2GROUP,&zgroup))) goto done;
+	    if((stat = nczmap_exists(zfile->map,zgroup)) == NC_NOERR)
+		nclistpush(subgrpnames,strdup(name));
+	}
 	stat = NC_NOERR;
 	nullfree(varkey); varkey = NULL;
 	nullfree(zarray); zarray = NULL;
+	nullfree(subgrpkey); subgrpkey = NULL;
+	nullfree(zgroup); zgroup = NULL;
     }
 
 done:
     nullfree(grpkey);
     nullfree(varkey);
     nullfree(zarray);
+    nullfree(zgroup);
+    nullfree(subgrpkey);
     nclistfreeall(matches);
     return stat;
 }
diff --git a/libnczarr/zmap.h b/libnczarr/zmap.h
index 064b977215..5c6acd82a9 100644
--- a/libnczarr/zmap.h
+++ b/libnczarr/zmap.h
@@ -62,10 +62,10 @@ implementing the key/object model.
 The list function takes a prefix path which has a key syntax (see
 above).  The set of legal keys is the set of keys such that the key
 references a content-bearing object -- e.g. /x/y/.zarray or
-/.zgroup. Essentially this is the set of keys pointing to the leaf
-objects of the tree of keys constituting a dataset. This set
-potentially limits the set of keys that need to be examined during
-search.
+/.zgroup or /g/.zgroup. Essentially this is the set of keys pointing
+to the leaf objects of the tree of keys constituting a dataset.
+This set potentially limits the set of keys that need to be examined
+during search.
 
 The list function has two primary purposes:
   1. Support reading of pure zarr datasets (because they do not explicitly track their contents).
diff --git a/libnczarr/zmap_file.c b/libnczarr/zmap_file.c
index ada1db6305..a2a40ec373 100644
--- a/libnczarr/zmap_file.c
+++ b/libnczarr/zmap_file.c
@@ -463,7 +463,8 @@ zfileclose(NCZMAP* map, int delete)
 }
 
 /*
-Return a list of simple names immediately "below" a specified prefix key.
+Return a list of simple names immediately "below" a specified prefix key
+(i.e. shallow listing).
 In theory, the returned list should be sorted in lexical order,
 but it possible that it is not.
 The prefix key is not included. 
@@ -962,7 +963,7 @@ platformdircontent(const char* canonpath, NClist* contents)
     default: goto done;
     }
 
-    /* We need to process the path to make it work with FindFirstFile */
+    /* We need to process the path to make it work with Windows FindFirstFile */
     len = strlen(canonpath);
     /* Need to terminate path with '/''*' */
     ffpath = (char*)malloc(len+2+1);
diff --git a/libnczarr/zsync.c b/libnczarr/zsync.c
index 3f4aae2020..b13edd85fc 100644
--- a/libnczarr/zsync.c
+++ b/libnczarr/zsync.c
@@ -405,7 +405,7 @@ ncz_decode_file(NC_FILE_INFO_T* file)
     root = file->root_grp;
     if((stat = NCZF_download_grp(file, root, &zobj))) goto done;
 
-    /* Decode the group metadata to get superblock */
+    /* Decode the group metadata to get only the superblock */
     if((stat = NCZF_decode_group(file,root,&zobj,NULL,(NCjson**)&jsuper))) goto done;
 
     if(jsuper != NULL) {