Voltage regulator for esp8266
That's the SPI Flash needed for the ESP8266. It is a standard SPI 32 M-Bit (4 MegaByte) flash eeprom 25Q32, so any similar data sheet for similar brands will work. It is not a regulator. The module you are looking at is the bare ESP8266 module.

It does not include the typical breakout board, which brings the pins out to standard 0.1" headers, has reverse voltage protection, a linear regulator, or extra features. Adafruit sells the completed module + breakout as the Adafruit HUZZAH ESP8266 breakout.