Coord info toggle, unsymbolized features, sublayer removal, disabled layer types, theme, highlight color, and service URL overrides.
Test plan: 18-global-settings.md
Default theme. Coord info visible. Sublayer removal allowed. Highlight layer available.
Dark backgrounds, light text, correct icon colors.
Light backgrounds, dark text.
Click a feature — highlight should be red instead of default aqua.
globalSettings.displayDateMode set to 'iso'. Click a feature with date fields to see ISO-formatted dates in details/data table.