If anyone else is having trouble getting the #AudioDescription feed to show up on the #WWDC stream, you can use:
Stereo AAC: https://events-live.apple.com/cmaf/live/2018335/0105pqsojoecckhtyzphnkxohhsqwacugmetmbhenyhwzbpy/avc_hd_audio_ad_en_2ch_aac_128.m3u8
Atmos: https://events-live.apple.com/cmaf/live/2018335/0105pqsojoecckhtyzphnkxohhsqwacugmetmbhenyhwzbpy/avc_hd_audio_ad_en_16ch_atmos_640.m3u8
Source: https://events-delivery.apple.com/0105cftwpxxsfrpdwklppzjhjocakrsk/m3u8/main.m3u8