GALEX [FUV] absolute magnitude (M_[FUV]) versus the X-ray luminosity of AGB and SySts. The X-ray AGB stars discovered by eROSITA are plotted with red symbols (squares = this work; circles = Schmitt et al. 2024); X-AGBs discovered by other X-ray surveys are shown with black circles; and SySts are shown with blue circles. The open symbols represent upper limits for M_[FUV], calculated at the GALEX detection threshold according to Montez et al. (2017). The arrow represents the far-UV extinction corresponding to one visual magnitude, assuming A_[FUV]/A_V = 2.6 (Cardelli et al. 1989). The solid line shows a least-squared fit (see Eq. 3) to all detected sources, while the dashed and dotted lines represent the 1-σ and 2-σ confidence levels, respectively.