Just noticed I left this one unanswered. Yes, correct above. It’s for storage of the blind filter. Mystery solved
Ohhhh well there ya go haha... yeah we were all quite puzzled at the time XD thanks for letting us know! Case cracked!
Profitec Pro 500, Rancilio Rocky Doser Grinder, 58.5mm Pullman Tamper, V60, Aeropress, Plunger, Behmor 1600