I would like to know what means ‘latent rule’, I think it is a juridical term, but I could find anything related to this, neither on the internet nor on dictionaries.
I think a more common term for this is unwritten rules. These "rules" refer to the unwritten guidelines and expected norms of a specific subculture – those behaviors and expectations that may not be specified in writing, but are adhered to nonetheless.
These rules could be found in a workplace (where they might also be referred to collectively as organizational culture), in a certain profession, in a classroom, or on a sports team. Sometimes, new people just follow the example of everyone else, without anyone ever needing to correct them by saying, "That's not the way we do things around here." When that happens – that is, when people adjust their behaviors based on the way every else is acting around them – I'd say that everyone is following the latent rules.
As for finding other references, there are some that can be found in books. It seems to be a rather erudite term, based on where I found it used. Here are a few excerpts I thought were interesting and helpful:
The sub-field of sociology known as ethnomethodology developed out of a scholarly preoccupation with the latent rules of social exchange and social discourse. (Bulmer & Solomos, 2013)
A lifetime's social training has enabled a person to assess the situation correctly and to produce the expected feeling according to social guidelines: 'a set of shared, albeit often latent rules.' (N. Malin, 2002)
There are also references to "pseudo rules," or "accepted rules," or "verbally formulated rules." Alternative locations for "real rules" are "latent rules," or "rules akin to but deeper than" the "paper rules." (J. Frank, 1973)
A system – or in our case a structure – can be said to exist if there is enough of a set of explicit, tacit, or latent rules that actors share and follow. (Reitan, 2012)
The adjective latent is probably used to describe that the rule is not presently active. In medicine, I often use latent infection which means the infection is not active.
This could be in the context of something that used to get passed or approved by the authentic bodies but since the rules are changed, now that something has to have new parameters to pass. This having said, the legal limit/parameters have been changed but that something could have been okay as per the latent rule.