How to calculate the finalsaplingroot?

I do not know the principles of calculation finalsaplingroot
like block 530082

“hash”: “00000000006656b89e9ba007cc6217efd6bdd62217e0f2f407a6aa13c09704c3”,
“confirmations”: 3002,
“size”: 7183,
“height”: 530082,
“version”: 4,
“merkleroot”: “facbdb862fceddad4babd694a59a9868ca9288bbc3668a5328d8fcff8db57c1f”,
“finalsaplingroot”: “554421b799bd5916b24b82f1c701b449083ab8852c1339bde7b63235b090d2dc”,
“tx”: [
“8799a7f68a503ebfa2f243be28c1af9512ff1122240d022ad56cc0ef26ab3fe5”,
“eedda8648423b3d4a59d018ce01e47b40c3d281c49d7d9e23fa0f167eda0d6dc”,
“f29e7554837273ac2fa2b384b3d0c9ba4298cc163ca079a3432e7daa5b57a4c3”,
“060bff33b347e59ea66dfa811519f12d2d031b0c0811b2d2f26a2faeb7332159”,
“9cab070a58ceac38c8004884f48380d89b510bbfae8ffb9e421d5993e63860ba”,
“5250b3a50b3876781f10b786da06db583f16b5dfff9c26732f97a52b27008945”,
“4b820e63cb26535ebfc57cd1148ea6d3fb13104633e30962bd6799506c95bdc2”,
“41e939628e9cdc7edbe4a66ea31b0cc519161dadb4efa6ff96121ec2f5150eba”
],
“time”: 1557487325,

Who can teach me?
thx

We’ll continue the discussion on the associated ticket: https://github.com/zcash/zcash/issues/4018