  The success of open source software (OSS) projects relies on voluntary
contributions from various community roles.Being a committer signifies gaining
trust and higher privileges. Substantial studies have focused on the
requirements of becoming a committer, but most of them are based on interviews
or several hypotheses, lacking a comprehensive understanding of committers'
qualifications.We explore both the policies and practical implementations of
committer qualifications in modern top OSS communities. Through a thematic
analysis of these policies, we construct a taxonomy of committer
qualifications, consisting of 26 codes categorized into nine themes, including
Personnel-related to Project, Communication, and Long-term Participation. We
also highlight the variations in committer qualifications emphasized in
different OSS community governance models. For example, projects following the
core maintainer model value project comprehension, while projects following the
company-backed model place significant emphasis on user issue resolution. Then,
we propose eight sets of metrics and perform survival analysis on two
representative OSS projects to understand how these qualifications are
implemented in practice. We find that the probability of gaining commit rights
decreases as participation time passes.The selection criteria in practice are
generally consistent with the community policies. Developers who submit
high-quality code, actively engage in code review, and make extensive
contributions to related projects are more likely to be granted commit rights.
However, there are some qualifications that do not align precisely, and some
are not adequately evaluated. This study contributes to the understanding of
trust establishment in modern top OSS communities, assists communities in
better allocating commit rights, and supports developers in achieving
self-actualization through OSS participation.
