Some rows that open subpages don't have an icon
The new Default Apps row, introduced with !989 (merged), doesn't have an icon:
However, several rows that trigger panels, which now open as subpages, have an icon. That's the case for the rows from the new Privacy and Accessibility panels, for example. The Proxy row, from the Network panel, and the rows from the Sharing panel also have icons (they were added recently by the way):
I'm not sure if this issue is actionable, but an icon for the Default Apps row would improve the visibility of this row and would also keep consistency.
Edit: there are also other rows, such as Night Light, which don't have an icon too:
Edited by Automeris naranja