I don’t think there’s schematic for newer OWL boards, unfortunately. You might try sending this question to Befaco contact form and see what they say.
From my (very limited) understanding, this is a decoupling (bypass) capacitor for reference voltage, so one end goes to VREF pin that you can clearly see here, another goes to the ground. So basically it simply filters noise from reference voltage and you should be able to replace it with a thru-hole 100 nF capacitor between that VREF pin and GND next to it. Keep in mind capacitor polarity - the negative terminal goes to the GND in this case.
This definitely needs double checking, but AFAICT you’re lucky that this might be the only electrolytic capacitor on that board that can easily be replaced by soldering to board pins directly You might be able to reuse the original SMD capacitor too if you put it on its side and solder to those 2 pins, maybe you’ll have to replace pins with longer ones in this case.