Chromecast hardware button?

[techlover10]

I feel stupid asking this question, but I can't seem to find any information online and don't want to mess with it too much. What is the one button on my Chromecast supposed to do?

 

[breadnatty08]

It's a reset button, it'll erase the setup you've done and bring you back to stock.
I had to use it the first time I set mine up since it was stuck.