Reviews - has that feature always been there?

[Newpetlover]

This sense of blind is very common in research and used in other languages.

@Newpetlover

Blind-
Definition number 4 in Merriam-Webster dictionary.

a

made or done without sight of certain objects or knowledge of certain facts that could serve for guidance or cause bias

a blind taste test

compare DOUBLE-BLIND, SINGLE-BLIND

b
having no knowledge of information that may cause bias during the course of an experiment or test

physicians blind to whether the test drug is administered