unciv is an extractor for some proprietary data archives from the 1999 Civilization spin-off Civilization: Call to Power..
You can read more, or download precompiled binaries on unciv's website: https://davidgow.net/hacks/unciv.html
In particular, it extracts the game's zfs archives, which contain the majority of the miscellaneous graphics (everything except tiles, sprites, and a few things like mouse cursors), as well as the sounds.
unciv also converts the game's rim graphics format to PNG, including both the 555 and 565 variants.
Simply run
cargo run <path to .zfs file>
The contents of the .zfs file will be extracted into the current directory.
Any file in the archive with the extension rim will be converted to a .png
when extracted.
If you wish for the original timestamps to be preserved, and you're running a
nightly build of Rust with the file_set_times supported, you can use
cargo run --features set-timestamps <path to .zfs file>
unciv depends on the byteorder (v1.3+) and png (v0.15) crates. Note that png has an absolute boatload of dependencies of its own, so you'll need to get those via cargo or some other means.
It's possible to build unciv with the rustc version included with Debian, just install
sudo apt install rustc cargo librust-byteorder-dev librust-png+deflate-dev
You can use Debian's packaged crates by following the Debian Wiki.
Have fun! — David