This is a tiny breakout board for the MAX7456 OSD IC. It has all the required components onboard. It measures 17mmx35mm and uses 5V. OSD stands for on screen display. It means using a TV as adisplay.
The minimal connection needs only 3 pins plus supply voltage. The chip is very simple to interface via SPI.
There are several modes to display the text. The chip works as an overlay or stand alone if no video source is applied.
Here is some simple BASCOM-AVR code: