How to efficiently get a sense of the meaning of a score on a non-aptitude test that you encounter in a journal article?
Tough question.

I'm going to assume that the question pertains to measures which lack all the information you've outlined: test manual, validity studies, website and key articles, item content and normative comparisons. If these assumptions are correct, then what you are a describing is an insufficiently explained measure. I will argue that we necessarily cannot know what such a scale means in any scientific sense.

A scale is a measure. A scientific measure is a process which generates evidence, i.e., observations that discriminate between different possible answers to a specific question. (Data may constitute evidence with respect to one question and not another.) The outcome of this discrimination, or analysis, is what the scale "means", i.e., the logically sound interpretation we may make on the basis of analyzing the evidence.

To determine whether a method does, in fact, generate evidence, we need to be able to replicate it independently. But the premises imply that we don't have enough information to do so. Because we cannot independently verify which hypotheses the evidence generated by the method discriminates between, if any, there is no way to know what it means.