From the man page: --ultra: unlocks high compression levels 20+ (maximum 22), using a lot more memory. Regardless, this reproduces with random other files

From the man page: --ultra: unlocks high compression levels 20+ (maximum 22), using a lot more memory. Regardless, this reproduces with random other files and with '-9' as the compression level. I made a mastodon post about it here: https://floss.social/@mort/115940378643840495 https://floss.social/@mort/115940378643840495