Hotspotd values

I have below output and I trying to dig into what the values for rrn and extended_capabilities. I know that rrn is related to 802.11k.
Output from ubus call hostapd.wlan1 get_clients

 "c8:58:95:xx:xx:xx": {
                        "auth": true,
                        "assoc": true,
                        "authorized": true,
                        "preauth": false,
                        "wds": false,
                        "wmm": true,
                        "ht": true,
                        "vht": true,
                        "he": false,
                        "wps": false,
                        "mfp": false,
                        "rrm": [
                                123,
                                0,
                                2,
                                0,
                                0
                        ],
                        "extended_capabilities": [
                                1,
                                0,
                                10,
                                2,
                                0,
                                64,
                                0,
                                64
                        ],
                        "aid": 3,
                        "signature": "wifi4|probe:0,1,221(0050f2,8)|assoc:0,1,59,54,33,36,45,54,70,127,221(0050f2,2),48,191,221(000ce7,8),htcap:117e,htagg:03,htmcs:000000ff,vhtcap:03907120,vhtrxmcs:0000fffe,vhttxmcs:0000fffe,txpow:1408,extcap:01000a0200400040",
                        "bytes": {
                                "rx": 553101,
                                "tx": 1239709
                        },
                        "airtime": {
                                "rx": 621537,
                                "tx": 6375554
                        },
                        "packets": {
                                "rx": 3075,
                                "tx": 2319
                        },
                        "rate": {
                                "rx": 6000,
                                "tx": 6000
                        },
                        "signal": -63,
                        "capabilities": {
                                "vht": {
                                        "su_beamformee": true,
                                        "mu_beamformee": true,
                                        "mcs_map": {
                                                "rx": {
                                                        "1ss": 9,
                                                        "2ss": -1,
                                                        "3ss": -1,
                                                        "4ss": -1,
                                                        "5ss": -1,
                                                        "6ss": -1,
                                                        "7ss": -1,
                                                        "8ss": -1
                                                },
                                                "tx": {
                                                        "1ss": 9,
                                                        "2ss": -1,
                                                        "3ss": -1,
                                                        "4ss": -1,
                                                        "5ss": -1,
                                                        "6ss": -1,
                                                        "7ss": -1,
                                                        "8ss": -1
                                                }
                                        }
                                }
                        }
                },