My rule is configured as:

"import/order": [ "warn" ],

So I assume this clause should be triggering, as I omit newlines-between:

newlines-between: [always|never]:
...
If omitted, assertion messages will be neither enforced nor forbidden.

But I still get a warning about empty lines:

import/order There should be no empty line between import groups at line 5 col 1

for the following code:

import foo from 'foo-core';

import {
    FooError,
} from 'foo-utils';

I expect no warnings about empty lines if newlines-between is not configured.

Probably it would be nice to have an explicit "ignore" value along with "always" and "never" which will be the default behavior if newslines-between isn't configured.