The jump-to-today action drew a generic calendar icon. It now draws the
current day number in an outlined box, on the same 24dp icon slot the bar's
spacing is measured against, so the bar says what day it is as well as
taking you there.
The number is held at a fixed size rather than following the font scale:
it is an icon glyph among stroke icons, and a growing two-digit day is the
width pressure #165 measured. The content description is unchanged.