Looks like this is the placebo-controlled trial https://clinicaltrials.gov/study/NCT03408886

I can't find full analysis but the primary autism-symptom outcome improved by 9% in treatment group and 4% in controls. I guess there is no statistical significance because that metric likely has high variance.

In abnormal stools there was 42% improvement in treatment vs 23% in control.

The combination of GI disorder and autism in these trials make blinding almost impossible. The patients will notice if the GI symptoms change. And the results seem to be that this fecal transplant has larger effect for the GI part anyway.