The B11 local-first push handed MPRIS the shared image-cache file://
URL on every online cache hit - but those files are named {md5}.img and
freedesktop mime maps *.img by extension to a disk-image type, so
GIO/KIO-backed widgets reject the artUrl (and the deferred upgrade task
replaced a working https push with the same dead URL within a second).
Online MPRIS art returns to the pre-B11 https passthrough (Tauri's
production contract); offline keeps the slice-3b file:// semantics; the
upgrade task is removed (re-introducing it requires cache files with
real image extensions). The (track id, art) metadata dedupe stays.
cc
vicrodh
53fefd3891