The accumulator requires an RSA modulus of unknown factorization, so we used the RSA modulus of unknown factorization from the world renowned RSA factoring challenge.
Is there any way to verify this since the source is not available? Just have to take your word for it and keep an eye on the blockchain for double spends?
Yes, that's the case for now. I assure you that the N value is in fact from the RSA modulus. Also Poramin is a well known cryptocurrency developer, who also made Vertcoin - the first coin that really made a good effort towards ASIC resistance (and one of top 5 most valuable cryptocurrencies this february)
How about a zero knowledge proof that you have a trustless setup. Use a zk-snark. That's what they are for.