Function of two pair of square solder pads on bottom of Arduino Pro Minis?

I have observed a pair of square solder pads on the bottom of the Arduino Pro Minis. This seems to be present on both the 3V and 5V models.

Pads of this type are typically used for solder bridges (for example, to set i2c addresses), but there are no markings which state the functions of these pads. Nor could I find any documentation on the site. One could also speculate that they could be used to solder on small SMT components, such as resistors.

Could someone please let me know what the function of these pairs square solder pads are?

If you look at the schematic, those show up as “Optional pullups for I2C lines.”

Thanks! :smiley: