Based onDTS-HD Master Audio track has been dropped. Around 5% of the size of the full disc.

mediainfo:

Complete name : Color Out of Space (2019) - making of documentary 4K BD remux.mkv 
Format : Matroska 
Format version : Version 2 
File size : 3.72 GiB 
Duration : 20 min 11 s 
Overall bit rate mode : Variable 
Overall bit rate : 26.4 Mb/s 
Movie name : Color Out of Space 
Encoded date : UTC 2020-02-22 10:02:49 
Writing application : MakeMKV v1.14.7 win(x64-release) 
Writing library : libmakemkv v1.14.7 (1.3.5/1.4.7) win(x64-release) 
Cover : Yes 
Attachments : cover.jpg