What does the "no rating" actually do?

when using the restriction with PIN-code to restrict which movies and shows that people can watch without using the PIN, there is a selection at the bottom that says “no rating”. but its unclear what it does?

does it restrict/allow to watch content that hasnt got a rating at all (i.e missing a rating)? or does it mean that it restricts/allows content that has a “no minimum age”, like its allowed for all ages?

Just a guess on my part but if a movie or TV show has an “all audiences” rating like “G” for general audiences or TV “Y” they still technically have a rating so I’d say the “No Rating” is referencing those files that have no ratings available.