`ninja check-functional`
On mainnet, check results against fulcrum:
```
./src/bitcoind -chronik -chronikelectrumbind="127.0.0.1:50001"
echo '{"jsonrpc": "2.0", "method": "blockchain.block.header", "params": [400000, 800000], "id": "test"}' | nc 127.0.0.1 50001
echo '{"jsonrpc": "2.0", "method": "blockchain.block.header", "params": [400000, 800000], "id": "test"}' | nc electrum.bitcoinabc.org 50001
```