  The final phase of the reionization process can be probed by rest-frame UV
absorption spectra of quasars at z>6, shedding light on the properties of the
diffuse intergalactic medium within the first Gyr of the Universe. The ESO
Large Programme "XQR-30: the ultimate XSHOOTER legacy survey of quasars at
z~5.8-6.6" dedicated ~250 hours of observations at the VLT to create a
homogeneous and high-quality sample of spectra of 30 luminous quasars at z~6,
covering the rest wavelength range from the Lyman limit to beyond the MgII
emission. Twelve quasar spectra of similar quality from the XSHOOTER archive
were added to form the enlarged XQR-30 sample, corresponding to a total of ~350
hours of on-source exposure time. The median effective resolving power of the
42 spectra is R~11400 and 9800 in the VIS and NIR arm, respectively. The
signal-to-noise ratio per 10 km/s pixel ranges from ~11 to 114 at $\lambda
\simeq 1285$ \AA rest frame, with a median value of ~29. We describe the
observations, data reduction and analysis of the spectra, together with some
first results based on the E-XQR-30 sample. New photometry in the H and K bands
are provided for the XQR-30 quasars, together with composite spectra whose
characteristics reflect the large absolute magnitudes of the sample. The
composite and the reduced spectra are released to the community through a
public repository, and will enable a range of studies addressing outstanding
questions regarding the first Gyr of the Universe.
