Tokyo Night keeps a renamed background pick in quattro
Pull request 15767, merged into quattro, moves a Tokyo Night background pick to the background with the same name under another number. On an upgrade from 4.0.x, a renumbered pick points at a missing file and the desktop falls back to Liftoff, including at 4.5.
The pull request says moving Liftoff to the front of Tokyo Night moved every other background up a number, so 0-winding-road became 1-winding-road. The existing WebP repair only looks for a WebP of the same name, so it does not repair that pick.
The migration moves the current background when it no longer opens, and each theme's remembered pick, to the one background with the same name under another number. A background that still opens, a person's own backgrounds, symlinks, and anything without exactly one match stay as they are.
emirb wrote that a QEMU install moved to edge with this migration showed the winding road again.