"These are not the robots you are looking for."
Translation:Dette er ikke robotene du leter etter.
I would say "this" here refers to "what is in front of you". "What you see here is not the robots you are looking for".
Or as has been said below, "dette" can be used to introduce something new. Also correct: "Det er en mann" ("it", even though mann is male). The concept also exists in English, you could say "it's a man". Norwegian just uses this more liberally.