`book::migration_guide`: DEFMT_LOG
- [#[global_logger]](./global-logger.md)
- [panic! and assert!](./panic.md)
- [Printers](./printers.md)
+- [Migrating from `v0.2.x` to `v0.3.0`](./migration-02-03.md)
- [Design & impl details](./design.md)
- [Interning](./interning.md)
- [Dealing with duplicates](./duplicates.md)
