802.11 Wireless LAN – Radio Information and Configuration

The HT Capabilities section provides the MCS values which are supported by the wireless network. These data rates can be used by both the AP and the client to send unicast traffic back and forth.

The HT Information section contains the Basic Data Rates supported (if any). The Basic Data Rates will be a subset of the supported data rates and are used for broadcast, multicast and management traffic.

The term packet can be ambiguous, so the standards often use 'acronym soup' to avoid such ambiguity. In particular, often 'packet' is taken to be the layer above 'frame' (i.e. level 3 of the OSI model).

However, as you have found out, that's not always so. Here the discussion is about physical (layer 1) IEEE 802.11 packets. So the frame is encapsulated within the data field of the packet, not the other way round.