Gyd9e Datasheet ((hot)) -

She soldered it to a breakout board. Wired Pin 1 to nothing. Pin 3 to ground. Pin 2 to 3.3V.

That is the output of the onboard 5V regulator. It can power your microcontroller (max 500mA). gyd9e datasheet

On page 3 of the GYD9E datasheet, you see the electrical characteristics. There is a column for Min , Typ , and Max . The engineer looks at the "Typ" value and designs for that. The master looks at the spread between Min and Max and sees a story of manufacturing variance. She soldered it to a breakout board