Are E>B regions essential for particle injection in relativistic magnetic reconnection?

During relativistic magnetic reconnection, X-points (E>B regions at vanishing guide field) have been proposed to play an essential role in injecting particles into the nonthermal population. Using fully kinetic particle-in-cell simulations at a range of magnetizations σ B 0 2/(4πn 0 m e c 2) = 12 -- 800, we study in detail how the particle energy gains up to the injection threshold γ inj = σ/4 are partitioned into work done inside E>B regions (unmagnetized), within one gyration after exit (re-magnetizing), and at all other times (magnetized). The magnetized channel supplies the largest part of the energy gain for about 95% of injected tracers at σ= 12 and about 65% at σ= 800. Most of the tracers in this magnetized majority never enter an E>B region before injection. We also compare these injection shares with the earlier studies that proposed an essential role for E>B regions. We conclude that E>B regions are neither necessary for injection nor the dominant direct contributors to pre-injection work by injection share in two-dimensional, nonradiative pair-plasma reconnection at vanishing guide field.