Hi.
What part of the unit are you referring to? Is this text in the code example?

  /*
  First we configure the wake up source
  We set our ESP32 to wake up for an external trigger.
  There are two types for ESP32, ext0 and ext1 .
  ext0 uses RTC_IO to wakeup thus requires RTC peripherals
  to be on while ext1 uses RTC Controller so doesnt need
  peripherals to be powered on.
  Note that using internal pullups/pulldowns also requires
  RTC peripherals to be turned on.
  */

Basically, this text means that if we wanted to configure internal pull-up or pull-down resistors, the RTC peripherals should be turned on. However, we don’t use internal pull-up or pull-down resistors (these should be defined in the code).

In our examples, we’re using external pull-down resistors (physical resistors that are connected to GND). See our schematic diagrams below:
https://rntlab.com/wp-content/uploads/2018/01/external_wake_up_button_bb.png
https://rntlab.com/wp-content/uploads/2018/01/external_wake_up_2buttons_bb.png

We don’t configure any pull-up or pull-down internal resistors in the code.

I’m not really sure if I understood your question or if this answers your doubts.

Let me know what you think.

Regards,
Sara