  As modern software extensively uses open source packages, developers
regularly pull in new upstream code through frequent updates. While a manual
review of all upstream changes may not be practical, developers may rely on the
authors' and reviewers' identities, among other factors, to decide what level
of review the new code may require. The goal of this study is to help
downstream project developers prioritize review efforts for upstream code by
providing a social network-based centrality rating for the authors and
reviewers of that code. To that end, we build a social network of 6,949
developers across the collaboration activity from 1,644 Rust packages. Further,
we survey the developers in the network to evaluate if code coming from a
developer with a higher centrality rating is likely to be accepted with lesser
scrutiny by the downstream projects and, therefore, is perceived to be more
trusted. Our results show that 97.7\% of the developers from the studied
packages are interconnected via collaboration, with each developer separated
from another via only four other developers in the network. The interconnection
among developers from different Rust packages establishes the ground for
identifying the central developers in the ecosystem. Our survey responses
($N=206$) show that the respondents are more likely to not differentiate
between developers in deciding how to review upstream changes (60.2\% of the
time). However, when they do differentiate, our statistical analysis showed a
significant correlation between developers' centrality ratings and the level of
scrutiny their code might face from the downstream projects, as indicated by
the respondents.
