  In the era of gravitational-wave astronomy, general-relativistic simulations
of compact objects play a role of paramount importance. These calculations can
be performed with the Einstein Toolkit, an open-source and community-supported
software for numerical-relativity and relativistic astrophysics. The code comes
with multiple solvers for Einstein's equations and for the equations of
general-relativistic magneto-hydrodynamics, along with a series of useful
diagnostics. However, analyzing the output of the Einstein Toolkit can be a
challenging task. Usually, the process involves a series of technical
obstacles, like combining data from different restarts or working with HDF5
files. Here, we present kuibit, a Python library that takes care of all these
low-level details (and many other more) and that provides high-level,
intuitive, representations of the data. Kuibit ships with a wide range of
features that include full support for 1-3D ASCII and HDF5 grid data, time and
frequency series, gravitational waves, and apparent horizons. With kuibit,
users can inspect most of the content of a simulation with just a few lines of
code. Importantly, kuibit is designed to be a code for the community: it is
user-friendly and does not require any proprietary software to run, it has
documentation and examples, and it is openly developed with emphasis on
extensibility and maintainability.
