favicons are the small icons that appear to the left of tabs you open in a browser.
they act as a form of branding and assist with usability by making it easier to differentiate between the sites you're using.
to the left is a favicon i made as practice. it's supposed to be the silhouette of a cat face with a diamond in the center. i created it by drawing a sketch in krita and recreating it as a vector in illustrator.