Steps to reproduce the issue

Install Joomla 4.2.3
Select Cassiopeia template
System -> Site Templete Styles -> Cassiopeia -> Advanced -> Font Sheme
Select Roboto (local)
There is a Warning that it might be illigal to load fonts from external sources.
Also activate the back to the top link.
Save configuration changes.
Now use FireFox Klar the secure version of FireFox to browse the Joomla website.

Expected result

Expected to see Hamburger Symbol in minimized main menue (like on smart phone) and arrow pointing up at the end of the web page.

Actual result

The Hamburger Symbol for the minimized main menue is not shown. Like it the symbol at the bottom of the webpage to scroll to the top is also not shown.

Now configure FireFox to NOT block external fonts and refresh the webpage. The Hamburger symbol and the scroll to top symbol are displayed.

Additional comments

So Cassiopeia still loads external fonts, even if local font is selected. This is also disturbing data protection rules, since the provider of the font might track who is loading the symbols.

I did not check if Cassiopeia is also accessing other external recources (like bootstrap or JavaScript), which would cause the same violation as the external font.