You typically do not download OpenWire.h as a standalone library from the Arduino Library Manager. Instead, it is provided through the following methods:
// Define serial port for RS485 (use Serial1 on Mega, SoftwareSerial on Uno) #define RS485 Serial
There are several methods to download and install the OpenWire.h library for Arduino:
to build your project, or are you trying to manually code an I2C communication