Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Reviewer's view of the efficacy data
FDA: NE reuptake inhibition and increased brain NE shown; evidence inadequate for a clear serotonin-receptor effect
“In summary (Table 87), pharmacology studies showed that viloxazine inhibits NE reuptake and increases the brain NE level by inhibiting NET; however, the evidence is inadequate to support a clear drug effect on serotonin receptors.”