While running tree in heartwood, I noticed some identifiers that look like they're generated from tests.

│   │   ├── z29SxZ1bXYxfNdvGgsTzyTAzgsnNH
│   │   │   └── P1eFDO
│   │   ├── z2CtychjSR19BAo6dAqZzApzomBon
│   │   │   ├── pgntxI
│   │   │   └── ZIouoa
│   │   ├── z2hq5wJVm9WavVTqzwvfWaqRDS7RQ
│   │   │   └── KQxO7T
│   │   ├── z2kpoo7JYkLvpEWj1dhvGCwmRM4Ac
│   │   │   └── Jxw6e0

They fall under radicle-node, so it might be from tests being run for that crate.