The indexer requires a full node.

I see the flag as `hgi`

:

```
$ curl -s "https://testnet.algoexplorerapi.io/v2/blocks/13819291" | jq
{
"block": {
"earn": 27162,
"fees": "A7NMWS3NT3IUDMLVO26ULGXGIIOUQ3ND2TXSER6EBGRZNOBOUIQXHIBGDE",
"frac": 9733995065,
"gen": "testnet-v1.0",
"gh": "SGO1GKSzyE7IEPItTxCByw9x8FmnrCDexi9/cOUJOiI=",
"prev": "blk-PLQJFVKQY5YKDU5P66ADL52WIGM44GOGBO6XYBFEWHAAMRFBMFYA",
"proto": "https://github.com/algorandfoundation/specs/tree/ac2255d586c4474d4ebcf3809acccb59b7ef34ff",
"rate": 19999960,
"rnd": 13819291,
"rwcalr": 14000000,
"rwd": "7777777777777777777777777777777777777777777777777774MSJUVU",
"seed": "FuzMUjU9svsxVMkzeb+xjKowKaabEuVYmcWl6f+ypk4=",
"tc": 15649796,
"ts": 1619616946,
"txn": "z3MximXiJdPy2yVbTDt965vCUT2Zgfqr/clB1ZRy/Do=",
"txns": [
{
"hgi": true,
"sig": "zyh2aINzuHkR88G1bIrKZldti2X+/5i4ZYWQuAn5XiDWhlZYk1Gna+SDII+LVA4/wd2TisrwwU1q9sWDOk7qDw==",
"txn": {
"arcv": "UWGOC45RXKERIWFF2Z6LR4VHSEDDHLRH7YLZQGS7WCZN5OSNZZLEDGWZ7A",
"fee": 1000,
"fv": 13819289,
"lv": 13820289,
"note": "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",
"snd": "SHTUSO6YCTH5NV74MU2HC4VOKFGX3NLOUVD5TCZCXQWDSX6JCE4SMZMOYA",
"type": "axfer",
"xaid": 408947
}
}
]
}
}
```