Found some evidential cue in aerospace suppliers literature (DuPont Nomex, ACP and Aramicore) with regards to square-cell honeycomb composite displayed on the debris marked 676EB... This type of core is called Over-Expanded Cell Aramid Honeycomb and allows the core to flex more in one direction than the other, "providing improved drapeability for the production of curved parts". Maybe I have a fixation, but the more I look at it, the more I see a relevant clue.