Sifting through 20 thousand Democratic National Committee's letters, released by WikiLeaks, is virtually impossible for only 4 days. But all that is currently sorted out and being actively discussed shows us how the archive is incomplete. However, the cleaning was carried out not on the principle "To reserve only the most scandalous facts'. On the contrary, they tried to give a façade of the internal workings of Democrats and not to hurt Clinton properly. Information concerning Sanders is uncut. But all the dirty laundry of the winner is something like lingerie. Once some potentially interesting material appears, the stored documents become unreasonably concise, ambiguous and fragmentary.
In other words, the letters do not contain anything that could seriously be used against the Democratic candidate for Presidency. On the other hand, "Russian hackers' attack" (although everyone knows about it only according to information provided by Democrats), aside from its obvious possibility to accuse yet again Trump of his friendship with the Kremlin without any proof, has saved Clinton from disclosures of Sanders' team. Judging from the preserved hints, Sanders' supporters gathered materials for the inner-party investigation regarding unacceptable methods of support for Clinton from the sidelines of Democrats, who have come out on top in the current presidential administration. After the appearance of the letters, any evidence collected in this area will be discredited by the previous scandal.
As a result, not bothering to come up with something that sounds convincing to explain the very fact of the archive's appearance (you really can't take literally the theory about the Russian hackers), Clinton has got an argument to continue Trump's baiting and shut mouth of the inner-party's opposition.