This is a daisy-chainable buck converter for 12 mm wide LED strips with 2 control pins, e.g. APA102. It is designed for 4 amps of output current at 5V, which is enough for about 60 LEDs (plus some safety margin).

The converter can be soldered between two segments separated by a few millimeters, with an additional two wires between each two sequential converters for the source voltage - the IC supports 6 to 28 volts, but the circuit was designed with 24V in mind.

The bottom of the PCB has a space for an optional 3v3 to 5v level shifter, allowing you to directly feed it from microcontrollers that do not use 5 volts.