-Searching in compressed files is @strong{slow} -- every request will
-lead to decompression of the file from the very beginning, so keeping
-uncompressed WARCs on compressed ZFS dataset is much more preferable.
-@command{tofuproxy} does not take advantage of multistream gzip files.
+@table @asis
+
+@item @file{.warc}
+Ordinary uncompressed WARC. Useful to be stored on transparently
+compressed ZFS dataset.
+
+@item @command{.warc.gz}
+GZIP compressed WARC. Multi-stream (multi-segment) formats are also
+supported and properly indexed.
+
+@item @command{.warc.zst}
+Zstandard compressed WARC, as in
+@url{https://iipc.github.io/warc-specifications/specifications/warc-zstd/, specification}.
+Multi-frame format is properly indexed. Dictionary at the beginning
+is also supported.
+
+It is processed with with @command{unzstd} (@command{redo
+cmd/unzstd/unzstd}) utility. It eats compressed stream from
+@code{stdin}, outputs decompressed data to @code{stdout}, and prints
+each frame size with corresponding decompressed data size to 3rd file
+descriptor (if it is opened). You can adjust path to it with @code{-X
+go.stargrave.org/tofuproxy/warc.UnZSTDPath} command line option during
+building.
+
+@end table