Septima — modern-codec 7z archiver for Linux

Why Septima?

Modern codecs, real tuning, and a native GNOME UI — a combination nothing else fills.

	Modern codecs	Real tuning	GNOME-native	One-gesture `.tar.zst`
File Roller / Ark	✗	✗	✓	✗
PeaZip	~	✓	✗	~
7-Zip CLI (`7zz`)	✓	✓	✗	✗
Septima	✓	✓	✓	✓

Everything driven by the bundled 7zz — no host filesystem access, portals only.

Format × codec × level, with the level range reacting to the codec. Dictionary, solid mode, and threads — with a live memory estimate.

Zstandard (1–22), Brotli, Fast-LZMA2, LZ4/LZ5, Lizard, plus LZMA2, PPMd, BZip2 — inside real .7z.

One switch for the BCJ filter, instead of the -m0=bcj folklore the Windows tool makes you learn.

Create a real .tar.zst / .tar.xz in one gesture, with full compression control.

Live progress and cancel, encrypted-archive password prompts, and split-volume output.

A Flatpak that ships 7zz and touches your files only through XDG portals — never the whole home directory.

The dialog covers the common knobs; the Advanced field passes any 7-Zip switch straight through.

-mfb=273 word size · -mmf=bt4 match finder · -mo=32 PPMd order.

-m0=ARM64 -m1=lzma2 for ARM binaries · -m0=Delta:4 for fixed-stride data.

-snl keep symlinks · -ms=100m solid block size · -mem=… modern encryption.

Honest about what's next. (Nested tarballs, presets, drop-to-open and the hash calculator already shipped.)

Post-extract actions — a "Show in Files" action and an optional "delete the archive afterwards" toggle.
Generate a checksum file — write a .sha256 / SHA256SUMS alongside a new archive.
In-archive edit — delete / rename entries, plus a "Test archive" action.
Self-hosted auto-updates — a signed Flatpak repo + .flatpakref so flatpak update pulls new releases.
Drag-out to extract — drag entries out of an open archive to a folder to extract them (dropping an archive in to open it already works).
Visual polish — custom styling and a bespoke app icon.