appBarRing

The ring around a bar button, and this one is not Microsoft's.

The other four are in the token dump — appBarHeightPx 72, appBarMiniHeightPx 30, appBarIconPx 48, appBarGlyphPx 26 — and came from the design guidelines. This one is nowhere, and that was established by looking rather than by not finding it in the obvious place: the WP8 SDK's design assembly carries ten control templates — Panorama, PanoramaItem, Pivot, PivotItem, LongListSelector, PhoneApplicationFrame, PanningLayer, PivotHeaderItem, PivotHeadersControl, Frame — and the ApplicationBar is not among them, because on Windows Phone it was a shell control rather than a XAML one. Its theme dictionary has no key containing "appbar", and neither file contains 1.5 in any stroke or thickness at all.

So there is no template to transcribe and this is this project's number, marked here the way the panorama's parallax coefficient is. 1.5 px is what a 48 px circle needs to read as an outline rather than a disc at this size; it has no better justification than that.