This exists exclusively in the popup, and not on Manage Jenkins which isn't really clear from your report (inferred from "Manage Jenkins" link).
.page-header__hyperlinks A has a margin-right: 0.25rem; from base-styles-v2.css.
Pinging fqueiruga – seems like the UI refresh caught more elements than expected due to the popup.
This exists exclusively in the popup, and not on Manage Jenkins which isn't really clear from your report (inferred from "Manage Jenkins" link).
.page-header__hyperlinks A has a margin-right: 0.25rem; from base-styles-v2.css.
Pinging fqueiruga – seems like the UI refresh caught more elements than expected due to the popup.