Somewhere along the way the spacing between the icon and text label in the main menu seems to have decreased. This seems to be the case for both AMC and non-AMC:
reference to the previous/correct version: https://web.archive.org/web/20191101063058/https://en.m.wikipedia.org/wiki/Main_Page
Per T292452#7400318 for consistency with Vector this should be an 8px margin.
The change should be done in core inside the mw-ui-icon library. Any no longer needed rules inside Vector should be removed.
QA Results - Beta
QA Results - Prod