they are m3u8 sources. just because it doesn't have the m3u8 on the end of the url doesn't mean they're not valid playlists.
this is the radio playlist. the other one is the same playlist the container has been producing since the beginning (which is the video playlist at whatever bitrate you specify in the container)...and is what is being referenced in this playlist. the whole point of this playlist is to use the video we already have authenticated for, and just overlay the radio on top of it. it works exactly as you'd expect in tivimate and kodi (and vlc for that matter), but channels ignores the second audio track.
#EXTM3U
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="en",NAME="English",AUTOSELECT=NO
#EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS,GROUP-ID="cc",LANGUAGE="en",NAME="English",INSTREAM-ID="CC1",AUTOSELECT=NO
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",NAME="English Radio",LANGUAGE="en",AUTOSELECT=YES,DEFAULT=YES,URI="http://192.168.88.142/radio/SDP"
#EXT-X-STREAM-INF:BANDWIDTH=6600000,RESOLUTION=1280x720,FRAME-RATE=59.94,CODECS="mp4a.40.2,avc1.640028",CLOSED-CAPTIONS="cc",AUDIO="aac"
http://192.168.88.142/playlist/SDP
#EXT-X-I-FRAME-STREAM-INF:BANDWIDTH=62000,RESOLUTION=384x216,CODECS="avc1.4d001f,mp4a.40.2",URI="514K/514_complete_iframe.m3u8"
#EXT-X-I-FRAME-STREAM-INF:BANDWIDTH=295000,RESOLUTION=960x540,CODECS="avc1.4d001f,mp4a.40.2",URI="2500K/2500_complete_iframe.m3u8"