How to add ESP8266HTTPClient library to project?

I do not see ESP8266HTTPClient lib in registry.
Is it somewhere in git? are there any plans to add it to registry?

The ESP8266HTTPClient library is part of the ESP8266 Arduino Framework. https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266HTTPClient

It is installed automatically to your system when you install the ESP8266 Platform.

To use the library, simpy add #include <ESP8266HTTPClient.h>

Thank you.

Just for my education, I see I can use std:: functions and they lead to c++ folder 10.3.0. What version of C++ is it?

As far as i can see:

C++ 11 on ESP32
C++ 17 on ESP8266