»Cognitions a priori« and »the intellect's own forms« are at bottom only two expressions for the same thing, hence in a manner of speaking synonyms.
Demnach sind »Erkenntnisse a priori« und »selbsteigene Formen des Intellekts« im Grunde nur zwei Ausdrücke für die selbe Sache, also gewissermaaßen Synonyma.
Accordingly »cognitions a priori« and »the intellect's own forms« are at bottom only two expressions for the same thing, hence in a manner of speaking synonyms.
The last sentence of the paragraph, drawn by »Demnach« from the chain before it, which the map formalizes as the checked argument a-schopenhauer-cognitions-a-priori-are-the-intellects-own-forms; the claim depends on it. The two expressions stand in Schopenhauer's guillemets, kept, and the two hedges, »im Grunde nur« and »gewissermaaßen«, are kept in the statement: the sentence claims a synonymy in a manner of speaking, not an identity of concepts. In the comparison x-thing-in-itself it stands in the row on what in the world of appearance is the subject's own, as the general form of what the appendix says of space at ZA II 534 and § 24 says of the three forms (c-schopenhauer-forms-in-consciousness-independent-of-objects). No link shares_premise_with is set, for the reason given on the page: Kant's statements in the map are about space, this one about a priori cognition as such.