System-arm32-binder64-ab.img.xz

: This is the most critical part. It indicates that while the CPU architecture is 32-bit, the Android Binder kernel interface is 64-bit. This is common in "mixed-mode" devices (e.g., a 64-bit kernel running a 32-bit userspace).

The filename refers to a specific type of Generic System Image (GSI) used in the Android ecosystem, typically for custom ROM development and Project Treble. system-arm32-binder64-ab.img.xz