  It is necessary to gather real refactoring instances while conducting
empirical studies on refactoring. However, existing refactoring detection
approaches are insufficient in terms of their accuracy and coverage. Reducing
the manual effort of curating refactoring data is challenging in terms of
obtaining various refactoring data accurately. This paper proposes a tool named
RefactorHub, which supports users to manually annotate potential
refactoring-related commits obtained from existing refactoring detection
approaches to make their refactoring information more accurate and complete
with rich details. In the proposed approach, the parameters of each refactoring
operation are defined as a meaningful set of code elements in the versions
before or after refactoring. RefactorHub provides interfaces and supporting
features to annotate each parameter, such as the automated filling of dependent
parameters, thereby avoiding wrong or uncertain selections. A preliminary user
study showed that RefactorHub reduced annotation effort and improved the degree
of agreement among users. Source code and demo video are available at
https://github.com/salab/RefactorHub

Software Engineering