It's really a pity that they do this now. Some of their older papers had actually quite some valuable information, comments, discussions, thoughts, even commented out sections, figures, tables in it. It gave a much better view on how the paper was written over time, or how even the work processed over time. Sometimes you also see some alternative titles being discussed, which can be quite funny.

E.g. from https://arxiv.org/abs/1804.09849:

%\title{Sequence-to-Sequence Tricks and Hybrids\\for Improved Neural Machine Translation} % \title{Mixing and Matching Sequence-to-Sequence Modeling Techniques\\for Improved Neural Machine Translation} % \title{Analyzing and Optimizing Sequence-to-Sequence Modeling Techniques\\for Improved Neural Machine Translation} % \title{Frankenmodels for Improved Neural Machine Translation} % \title{Optimized Architectures and Training Strategies\\for Improved Neural Machine Translation} % \title{Hybrid Vigor: Combining Traits from Different Architectures Improves Neural Machine Translation}

\title{The Best of Both Worlds: \\Combining Recent Advances in Neural Machine Translation\\ ~}

Also a lot of things in the Attention is all you need paper: https://arxiv.org/abs/1706.03762v1