“Word Of Dante is stuff the creators haven’t said is true about their universe — but everyone assumes it is true because an independent authority, scholar of the work, or Big Name Fan has said it — often with supporting arguments. It’s a kind of ascended Fanon. A more literary criticism friendly technical term for it would be deuterocanon.” [. . .]    —TV Tropes

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Some examples:
-“Alien Geometries – While Hell and Purgatory have clearly defined geography, that of Paradise is more complicated. The spheres of Heaven correspond to the celestial spheres of a geocentric universe, but can equally well be seen as orbiting around God in the Empyrean, or as all existing in the same space. To enter Paradise or cross between the spheres, one must Ascend To A Higher Plane Of Existence, rather than doing any physical climbing. The structure of Heaven has been interpreted as an early description of the fourth-dimensional hypersphere.”
-“And I Must Scream – The Inferno is made of these. In particular, suicides are turned into trees. They can scream, when someone breaks off a branch. And traitors are just frozen. Their eyes are actually frozen shut with their tears. The worst off are probably the ones at the very bottom, completely frozen in ice in grotesque positions. There’s also the penance for the sin of Pride in the Purgatorio: the sinners are made to carry boulders, the weight of which is proportional to the sin’s weight. Dante even remarks that the punishment is the simplest, and yet quite terrible.”
-“And That’s Terrible – Dante really hated corrupt priests.”
-“Author Avatar – Purgatory has seven levels corresponding to the Seven Deadly Sins. Dante experiences the penances for only three: Pride, Anger, and Lust. Translator Dorothy L. Sayers commented that these were precisely the three faults people tend to accuse Dante of, so sharing these penances was probably a deliberate confession on the poet’s part.”

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