The normal way to access localstorage objects is via getters and setters:

localStorage.setItem('myCat', 'Tom');

and

const cat = localStorage.getItem('myCat');

But as described here, it is also possible via properties and array like access:

localStorage.colorSetting = '#a4509b';
localStorage['colorSetting'] = '#a4509b';
localStorage.setItem('colorSetting', '#a4509b');

In foxhound, the correct function argument is not always reported when using the direct properties access.