ESPFlash is a convention for programming header connections to PCBs designed with the Espressif ESP8266, ESP8285, and ESP32 MCUs.
The convention allows for both 1x6 and 2x3 format headers, in either 2.54mm (0.1") or 1.27mm (0.05") sizes.
More information is available at https://www.superhouse.tv/espflash
Ideally I want other people to use this header format to make their own programmers, but to make it easy to incorporate into your project without having to make a programmer I've also made my "ESPFlasher" implementation available for purchase.