Fiducial synthetic observation OBSfid based on the Braginskii-MHD simulation rescaled with the values of Eqs. (6), (9), and (11) at 0.25 R₂₀₀ in a Perseus-like cluster. From left to right: emission measure fluctuation δEM, spectroscopic temperature fluctuation δT_s and emission-weighted velocity v_ew maps. Top: line-of-sight integrated input fields from the rescaled MHD simulation. Bottom: output fields reconstructed from the synthetic observation OBSfid. The colourbars are set according to the input quantities. The values of the thermodynamic fluctuation fields are given in percents of the average background quantities (see Eq. (E.3)).