issue_comments: 1019849836

It's not at all tricky to implement the listing of groups in a NETCDF4 file, at least not for the "netcdf4" engine. The code for that is in my OP above: ```python

def _xr_nc4_groups_from_store(store): """List all groups contained in the given NetCDF4 data store

Parameters
----------
store : xarray.backend.NetCDF4DataStore

Returns
-------
list of str
"""
def iter_groups(ds, prefix=""):
    groups = [""]
    for group_name, group_ds in ds.groups.items():
        groups.extend([f"{prefix}{group_name}{subgroup}"
                       for subgroup in iter_groups(group_ds, prefix="/")])
    return groups
with store._manager.acquire_context(False) as root:
    return iter_groups(root)

```