Historical and smoothed variables

I would like to better understand the the graph of Historical and Smoothed Variables that comes as a result of Bayesian Estimation.
Will someone please interpret these graphs please?
Thank you

If we are talking about the same graph, then:

The Historical and smoothed variables plot is generated by the estimation-command when either maximum likelihood estimation (ML) is used or Bayesian estimation without the smoother-option. It is stored in the main folder. The
dotted black line depicts the actually observed data, while the red line depicts the estimate of the smoothed variable (“best guess for the observed variable given all observations”), derived from the Kalman smoother at the posterior mode (ML) or posterior mean (Bayesian estimation). In case of no measurement error, both series are identical.