...
<dataset> must be one of: "GEOMETRY_DATASET","MESH_DATASET","MESH_DATA_DATASET","RESULTS_DATASET",
"MESH_PREFERENCES_DATASET","GLOBAL_PREFERENCES_DATASET","LAYERS_DATASET","GROUPS_DATASET","GROUP_ENTITIES_DATASET",
"CONDITIONS_DATASET","CONDITION_ENTITIES_DATASET","MATERIALS_DATASET","INTERVALS_DATASET","DIMENSIONS_DATASET",
"UNITS_DATASET","LABELS_DATASET","LOCAL_AXES_DATASET","BACKGROUND_IMAGE_DATASET","RENDER_DATASET",
"EMBEDDED_DISTANCES_DATASET","VIEW_DATASET"
Note: Can set the flag off all kind of datasets with GiD_ModifiedFileFlag set|get ?<value>?