The home page says the MicroBBPS fits in standard solderless breadboards, so I figure it means this type:
Trying to fit it into these breadboards I have no luck with the smaller one and can force it into the larger one but it bends out the power rails.
In both latest release and main branch spacing between outermost power rail pin centres is around 1.89".
Manually measuring on my cheap standard breadboards I get from 1.80" to 1.84" between outermost power rail pin centres give or take a couple hundredths of an inch.
Standard cheap breadboard power supplies that fit these breadboards seem to be off the standard pin pitch between power rails headers by half a pin spacing. They fit nicely in the power rails but don't in the body of the board. Three types I have all measure to about 1.85".
So it seems to me that the power rail headers on the MicroBBPS are about 0.05" too wide for these breadboards.