"Dynamic background" gains "Wallpaper" and "Wallpaper, blurred". The
picture is the desktop's wallpaper — Plasma's appletsrc (the containment
on screen 0, image plugin only; a wallpaper package resolves to its
largest bitmap, a slideshow folder to its first image), GNOME through
gsettings (the dark variant under a dark scheme), Windows' current
TranscodedWallpaper, macOS through System Events — or an image the user
picks (Settings > Appearance > Background image), which outranks it. The
resolved path and its mtime are memoised, so the frequent refreshes
(session entry, a mode switch, the window coming to the front) republish
nothing while the file holds.
"Wallpaper, blurred" sends the picture through the same atmosphere pass
Blurred art gives the cover, held still. "Wallpaper" shows the part of
the wallpaper that lies behind the window, lightly blurred under the
half-alpha chrome, at most a screen-sized texture: the window's place on
the screen comes from Qt where the platform tells it (X11, macOS,
Windows); Wayland hides window positions, so there the crop is centred
until the Plasma window-management protocol is wired. Neither mode waits
for a playing track. Six new strings in eight catalogs.
cc