What does the symbol '&$checked' mean

Question

import React from \'react\';
import Checkbox from \'@material-ui/core/Checkbox\';
import { createMuiTheme, makeStyles, ThemeProvider } from \'@material-ui/core/style         


        

Answer 1

'&$checked' means you can override the element after checked.

And in your case, you are overriding the colour of checkbox after checked it

"&$checked": {
      color: theme.status.danger
    }

PFA for detail