Looks like you have google fonts disabled? They're supposed to be icons, but since they can't be loaded, the text gets shown instead.
They can also confuse search engines (Try a Google search for "keyboard_arrow_up" and scroll down a few results for instance, Bing too if you put it in quotes).
Webmasters should use SVGs or bitmaps with appropriate alt or aria attributes; but it's easier to just load in a font and hope that it loads fast enough to not cause problems / that the user doesn't override it