The larger holds a Raspberry Pi 2/3/4 and a half-width breadboard.
The smaller is made for a Raspberry Pi Zero.
Nothing too complicated - just handy prototyping cases in solid and slotted bottoms.
Both accept 4x M2.5x4 (or M2.5x5)
Breadboard can be stuck to base, or simply held temporarily by friction.
Shown in Galaxy Black PETG
.3mm Layer Height
20% Infill - Grid
The author hasn't provided the model origin yet.