Query parameter key used to pass the serialized current theme main holds at the moment a window
is created, so that window paints its first frame — and bakes its web views' stylesheets — with
the theme the app is actually on instead of the default followed by a flash.
Absent when main has nothing to pass — a profile that has never chosen a theme, or one whose
theme is still only in a renderer's own store awaiting its one-time handover. A renderer that
does not find it falls back to what it can read for itself, and then to the default.
Query parameter key used to pass the serialized current theme main holds at the moment a window is created, so that window paints its first frame — and bakes its web views' stylesheets — with the theme the app is actually on instead of the default followed by a flash.
Absent when main has nothing to pass — a profile that has never chosen a theme, or one whose theme is still only in a renderer's own store awaiting its one-time handover. A renderer that does not find it falls back to what it can read for itself, and then to the default.