The Purvas do not survive in any form. What is known of them comes entirely from later Jain canonical descriptions of their existence and content, not from the texts themselves, and no source outside the Jain tradition independently confirms either their content or that they trace to Mahavira's own teaching.
What would resolve this The discovery of a surviving Purva manuscript, or an independent near-contemporary reference describing their actual content, would let the tradition's account of their origin be checked against something other than later restatement of the same tradition.
OpenJain textual history and IndologyPadmanabh S. Jaini, The Jaina Path of Purification