  The third gaia data release (DR3) provides a wealth of new data products. The
early part of the release, Gaia EDR3, already provided the astrometric and
photometric data for nearly two billion sources. The full release now adds
improved parameters compared to Gaia DR2 for radial velocities, astrophysical
parameters, variability information, light curves, and orbits for Solar System
objects. The improvements are in terms of the number of sources, the variety of
parameter information, precision, and accuracy. For the first time, Gaia DR3
also provides a sample of spectrophotometry and spectra obtained with the
Radial Velocity Spectrometer, binary star solutions, and a characterisation of
extragalactic object candidates. Before the publication of the catalogue, these
data have undergone a dedicated transversal validation process. The aim of this
paper is to highlight limitations of the data that were found during this
process and to provide recommendations for the usage of the catalogue. The
validation was obtained through a statistical analysis of the data, a
confirmation of the internal consistency of different products, and a
comparison of the values to external data or models. Gaia DR3 is a new major
step forward in terms of the number, diversity, precision, and accuracy of the
Gaia products. As always in such a large and complex catalogue, however, issues
and limitations have also been found. Detailed examples of the scientific
quality of the Gaia DR3 release can be found in the accompanying
data-processing papers as well as in the performance verification papers. Here
we focus only on the caveats that the user should be aware of to scientifically
exploit the data.
