Using :hover to display additional information or elements is a very useful technique but a big drawback to using the hover pseudo-class is that they are usually not accessibility-friendly. Not everyone uses a mouse and some users have visual impairments, so they rely on screen readers or the keyboard -- two functionality that don't technically hover.
Luckily the CSS spec gives us a gift to pair with :hover: :focus-within. With :focus-within developers can modify styles of elements when an element or its parent has keyboard focus!