: Adding or refining specific virtual machine versions (e.g., pc-*-2.6 ) to maintain compatibility between older and newer emulator builds.
: Fixing bugs or adding features like memory hotplug (memhp) support and forcing gaps between memory addresses. v2-2-2-pc
: Optimizing how the system tracks changes in memory after removing blocks of RAM to improve performance. : Adding or refining specific virtual machine versions (e