The extension board overhang shown in the pictures has been fixed in the provided model.

This block should fit any standard size breadboard.

As for the GPIO breakout board, it was designed to work with the one from this starter kit: https://store.freenove.com/products/fnk0020

I can't guarantee that it would fit any others, but the hole dimensions are as follows:

Small hole:

• 16mm long
• 12mm wide
• 36mm deep

Long end:

• 56mm long
• 7mm wide
• 7mm deep