iw shows the used bitrate and indicates the used IEEE 802.11 standard by its listed capabilities.
Read your interface name from the
iw dev output, and use it within
iw dev <name> link
Example output when associated with a legacy (non-802.11n) AP:
tx bitrate: 36.0 MBit/s
"MCS index", indicating a 802.11n AP:
tx bitrate: 300.0 MBit/s MCS 15 40Mhz short GI
"VHT", indicating support for 802.11ac:
tx bitrate: 86.7 MBit/s VHT-MCS 8 short GI VHT-NSS 1
Compare this with the Linux driver 802.11n table. You'll see how the example "MCS 15 40Mhz short GI" 300 MBit/s corresponds to a row within the "HT40 rates" for the "short 400ns GI" column.
To see what your Wi-Fi adapter is generally capable of, independent of the AP link, run
iw phy0 info (synonymous to
iw list) and look for keywords like HT (802.11n) / VHT (802.11ac, (Very) High Throughput), MCS (Modulation and Coding Schemes) index number and long/short GI (Guard Interval).
For more explanations, continue with this Super User answer.