How to decode x-amz-meta-file-acl

When using an SMB file share on S3 File Gateway, the file level ACLs at the windows as stored as object meta data on s3. What format is this attribute being stored as? How can I decode it to a human readable format?

"file-acl" or "x-amz-meta-file-acl"

$ aws s3api head-object --bucket storage-gateway-user1581 --key user1581/filename.xlsx
{
    "AcceptRanges": "bytes",
    "LastModified": "2023-10-25T19:58:22+00:00",
    "ContentLength": 14984,
    "ETag": "\"25b3b9c62nned0fgffat5b28f3b21d6f\"",
    "ContentType": "application/octet-stream",
    "ServerSideEncryption": "AES256",
    "Metadata": {
        "user-agent": "aws-storage-gateway",
        "user-agent-id": "sgw-84178D7XD",
        "aws-sgw": "fe2e0cfb07ecdf5d1c094b26c5630853780877025edfb37f3f2b6c0cf2407694",
        "file-acl": "EQUFFajv2K4G2IvQ7QSHyu/ZAtHUGgUFFajv2F6G2IvQ7QSHyu/ZAoEEjAQDAACQqQUFFajv2K4G2IvQ7QSHyu/ZAtb4xAYAAJCpBAAVqO/YrgbYi9DtBIfK79kCs9WIBgAQ+f8BGQA=",
        "file-ctime": "1698263901160000000ns",
        "file-dosattr": "32",
        "file-owner": "503483",
        "file-permissions": "0777",
        "file-group": "67179",
        "file-mtime": "1696618082735595800ns"
    }
}