What is this component?

I found it in the bottom of my box.

How to attach an image

I'll go with I2C backpack for 1602 display.

Shame its too out of focus to read the chip part number - which is useful to lookup.

it looks in every possible way like an I2C backpack, as noted above. including the A0 A1 A2 jumpers for address changing

what else looks exactly like an I2C backpack?

Well, it does pass the duck test for I2C LCD backpack.
Looks exactly like the ones in my parts bin. I bet that chip is a PCF8574.