1.21.9 - 26.2

New pack format, pack_format -> min_format & max_format

Also I've noticed that if the last child of an alternatives entry is another alternatives without any condition (which is commonly used pattern for if|else branching in this pack), the last child's children can be brought out one level to the parent's children list so that it acts as if|elif|else. This change would reduce file sizes a bit, but performance-wise it would not be very noticeable.

(2025-12-10) Fixed: 1.21.9 ZIP file contents were mistakenly nested in an extra directory.