They share a rule: resonance_outside_preoccupation. That's the actual grouping criterion, not any surface theme among the tasks themselves.
Jobs pruning and orphaning, knowledge rescanning, email polling. Small things.
Overcast skies, soft light. Muted, hazy, damp. Not the starry moments or the crisp ones. The "something's coming, or just about passed" ones. The harbor boats bob without urgency.