Explain unfamiliar code step by step

Explain the {{language}} code below to a developer who is new to this codebase.

1. One paragraph: what it does and when it runs
2. Walk through it in order, block by block
3. Inputs, outputs and side effects (files, network, database, global state)
4. Anything risky or surprising: edge cases, error handling gaps, performance traps
5. Questions I should ask the author

Don't rewrite the code. If something depends on code that isn't shown, say so.

```
{{code}}
```