  We present a probabilistic model built for the optical cross-match between
the SRG/eROSITA X-ray sources and photometric data from the DESI Legacy Imaging
Surveys. The model relies both on positional and photometric information on
optical objects nearby X-ray sources and allows performing selection with
precision and recall $\approx94$% (for $F_{\rm X,0.5-2}>10^{-14}$
erg/s/cm$^2$). With this model, we calibrated positional error of the
SRG/eROSITA sources detected in the Lockman Hole: $\sigma_{\rm corr} =
0.87\sqrt{ \sigma_{\rm det}^{2.53} + 1.12^2}$. The model will become a part of
the SRGz system for data analysis of the X-ray data obtained from the all-sky
SRG/eROSITA survey.
