In this sentence, which part is quoted?
It's no accident that the quote unquote golden period of Latin literature ends during this time.
It is from a TV documentary.
It's not entirely clear. Like "so-called," this [informal] usage of "quote unquote" generally refers to the object or idea immediately following it. In this particular case, however, it could be read as either "golden period" or "golden period of Latin literature." The former would mean that "the age of Latin literature known as 'the golden period' ended during this time," while the latter would mean that "the age known as 'the golden period of Latin literature' ended during this time." It may be possible to discern based on the context.
The simplest way to read this is the "golden" period of Latin literature.
The phrase "quote-unquote" is inserted to indicate that the writer has doubts or denies the objective truth of the word or phrase that follows (or precedes) it.
But there is no doubt that Latin literature exists, nor that there are periods of time when it was being written. The only part that seems questionable is the assertion that a particular period was "golden" (ie better than all the others). I'd expect the author to explain why they don't think that the adjective "golden" should be used — either the other periods were just as good, or the "golden" period was not as good as the adjective suggests.