The code on Github is still a rewrite of cryptonote in a new language. Before you dismiss that, I think you should take into consideration how hard that is. It requires a deep understanding of cryptography and blockchain. If anybody that can even understand that piece would like to come forward with bugs/security flaws in the Github code, I will allow them to cast a shadow of doubt on the years of experience required to write it (or read it properly).
What Dero devs accomplished so far was a really hard task done very quickly and it seems with rather few bugs they needed to patch. It tells you they are very talented and hard working. There are very few developers in the whole crypto space who can be compared to them. They must have their reasons for the secrecy surrounding the project and we should respect this.