This merge request constructs 3x3 blocks of towers (gBlocks), and saves them to storegate for transient access (with a change to the TriggerEDM they can be added to the AOD).
We then take the highest 4ET gBlocks per FPGA, and save them to the Run2 jet container for processing.
[1] https://indico.cern.ch/event/816565/contributions/3446614/attachments/1861601/3059710/Miller_gFEXStatusPlans_13Jun2019.pdf (slide 16)