Values of this type are strings. Possible values are:

"per-origin"

All other tabs with the same origin as this tab will have the zoom changes applied to them. This scope is only available if tabs.zoomSettingsMode is "automatic".

"per-tab"

Zoom changes only take effect in this tab, and zoom changes in other tabs will not affect the zooming of this tab. Also:

• in Firefox the zoom level persists across page loads and navigation within the tab.
• in Chrome-based browsers zoom changes are reset on navigation; navigating a tab will always load pages with their per-origin zoom factors.