issue_comments: 1065424051

So it looks like changing

https://github.com/pydata/xarray/blob/d293f50f9590251ce09543319d1f0dc760466f1b/xarray/backends/api.py#L1280-L1301

to

```python def _validate_datatypes_for_zarr_append(store, dataset): """DataArray.name and Dataset keys must be a string or None"""

def check_dtype(vname):
    store_dtype = store.get_variables()[vname].dtype
    dataset_dtype = dataset[vname].dtype
    if not store_dtype == dataset_dtype:
        raise ValueError(
            f"Mismatched dtypes for variable {vname} between Zarr store on disk "
            f"and dataset to append. Store has dtype {store_dtype} but dataset to "
            f"append has dtype {dataset_dtype}."
        )

for vname in dataset.data_vars:
    check_dtype(vname)

``` could work?