Each of those peaks sent every 1s correspond to the transmission of an advertising BLE package over the three advertising channels.
The idle power consumption between peaks is ~4.6 μA, that is similar to declared 4 μA declared in the datasheet for sleep consumption with all SRAM retention.

I wanted to know it's power consumption so I connected it to my Nordic Power Profiler Kit II. During normal operation the average power consumption is 21 μA.

• Several test points for debug. (GND, 3V3, RST, P9 and P10). I initially thought P9 and P10 would be SWD IO and clock, but they are connected to pins 8 and 9, instead of pins 3 and 4, where SWD pins are located according to the datasheet. In a different reference design, they are labeled as TX and RX.
• PCB is labeled as iTag13-RSH V3-20250417. It's a very recent design.

As a summary, the design includes:
• BLE microcontroller
• 16 MHz crystal for the microcontroller.
• Chip antenna
• DC/DC external passive components
• Buzzer (probably driven from Q1 bipolar)
• Pushbutton used for ON/OFF
• A couple not-assembled ICs. My guess is that U3 footprint might belong to an IMU sensor.