Hi! It’s an EUD map. Also the map must be locked, since you can’t open it open in SCMDraft 2. And even if it were unlocked, you couldn’t do much without the source files (if it’s a very complex EUD map), since EUD involves numbers, and you wouldn’t understand a thing of what’s there. Only the creators have the source files. Those source files are created within an EUD editor, like EUD Editor 3. Someone correct me if I’m wrong.
Here’s a guide about EUD:
http://www.staredit.net/topic/14226/
EUD Editor 3:
http://www.staredit.net/topic/18169/
More tools / EUD tools over here:
http://www.staredit.net/forum/41/
An extreme example of EUD map (this map works only with SC 1.16.1):
https://www.youtube.com/watch?v=JUQcozMPL8I
Here are some sites where you can find maps / EUD maps:
https://repmastered.app/maps?mapClass=C&nameClass=HK
https://bounding.net/search
https://kkmg2012.tistory.com/