Currently the clist tile_cache is "managed" during the clist writing that knows the size of the tile_cache and writes tiles to bands so they will be available when needed for rendering the band. This can result in a tile being written to more than one band and makes the cache management logic less obvious and makes the clist reader tile_cache size very sensitive to the size assumed during writing. By writing tiles to "pseudo bands" similar to the way ICC profiles are handled allows the reader to manage a tile cache since it will be able to load a tile if needed for a band if it isn't already in the cache.
This shouldn't be assigned to ghostpdl-bugs. Since Ray opened it, and its a clist enhancement, assigning back to Ray.