Although the SFOS community did express some interest in the 3.5 mm jack in the polls earlier, there's no headphone jack. The expected device sales volume probably would not cover the added engineering cost from such modifications to the mainboard reference design at the announced price point.

Some time ago I also thought that no 3.5mm jack is a deal-breaker, but I bought super cheap jack-usbc adapter that is 5cm long and it works pretty well.