Decompression and checksumming overlap with parsing via a pipe, and a concrete-typed varint reader removes per-byte interface calls (0.39s -> 0.29s for 458K nodes).
Cell canvas renderer with frame cache and a perceptual 256-colour quantizer; responsive geometry (large/medium/small/too-small); squarified treemap with nested previews, LOD grouping, category colouring and adaptive labels; spatial arrow navigation with stable NodeID selection; zoom and breadcrumbs; modal system (info, help, confirm, save); list, file-type, top-N, scan-info, duplicate and comparison views; live search/filter; mouse support; move-to-trash.
Andy Dixon