Function fetch_pruned_leaves 

async fn fetch_pruned_leaves(
    provider: &LightClientProvider,
    heights: Range<u64>,
) -> Vec<Leaf2> 

The leaves at heights, which the data pruned height says are gone, from the query module’s peers through its light client, retrying until they arrive. The light client verifies leaves of every protocol version, and one proof covers the run: it proves the last leaf final and chains the rest to it. The loop needs each leaf once, so the leaves are stored neither in this database, where the pruner would only delete them again, nor in the light client’s cache.