Upper limits on gamma-ray flux at 95% confidence level for time windows considered in our analysis (10, 100, 1000 and 10 000 s). The orange dashed line represents the median value of ULs on individual FRB events, while the orange band is obtained from the 10% and 90% quantiles of these values, while the blue points are the ULs obtained with the stacking analysis. The grey dashed line shows the upper limits derived from the stacking analysis performed on a sample of background sources.