A library for driving LiquidCrystal displays (LCD) by using the I2C bus and an PCF8574 I2C adapter.
There are modules that can be soldered or stacked to the display that offers a I2C interface for communication instead of the 8+ digital lines that are used to send data to the display.
Most of these modules used the internal wiring that is supported by this library. If you use a module with a different wiring you can adjust this in the code (see comments).
See the web site for more details and pictures: https://www.mathertel.de/Arduino/LiquidCrystal_PCF8574.aspx