A bstract We analyze the global symmetries and anomalies of 4d $$ \mathcal{N} N = 1 field theories that arise from a stack N M5-branes probing class flux backgrounds. These backgrounds consist resolved ℂ 2 / ℤ k singularity fibered over smooth Riemann surface genus g ≥ 2, supported by non-trivial G 4 -flux co...