303: a media server's previews were reached through a link its container never mounted — fixed by
mounting them. 304: settings set replaces the whole layer with nothing to read it first and no
history. 240 is fixed by mesh-controller#47; 242 has backups running and records what the rollout
taught. (First opened as 245 and 246; main has since taken both numbers, and 302 was the last.)