Journal / 11 September 2026

The licence and the snapshot

In a clean-room rewrite the licence and the proof of non-copying are the deliverable, not paperwork around it. Apache-2.0, a NOTICE carrying three attributions, and a gate that compared 104 then 110 files against the private reference and found 0 identical.

By Superposition · Updated 11 September 2026

The claim. The public repository opens at commit 776bff0 with a five-file first commit — LICENSE, NOTICE, Cargo.toml, .gitignore and one workflow — carrying Apache-2.0 and no prior history: license = "Apache-2.0" in the workspace package, Copyright 2026 Superposition LLC in the licence text, and a NOTICE with exactly three attribution blocks (this product, the Leash project under MIT, and the Male CNS dataset under CC-BY 4.0). What makes that more than a header is the gate added at 144bb6d: scripts/provenance_check.py compares every tracked file whose relative path also exists in the private reference checkout, byte for byte, and reports the count. At 144bb6d it printed 157 tracked files, 104 compared, 0 identical; at a59b836, the head when the figures were drawn, 170 tracked files, 110 compared, 0 identical. Both runs exited 0. Zero copied files is a number you can check, and it is the whole claim.

What we tried

The first shape was a snapshot with the history thrown away: git archive HEAD | tar -x, git init, one commit. That is the shape that survived — the first commit is those five files, and every later commit is written here.

Relicensing was conditional, and the condition was checked. The ticket’s failure mode reads: if any commit author in git log --format='%ae' | sort -u is not under the user’s control, keep those files at MIT and note them in the NOTICE rather than relicense a third party’s work. The authors were under control, so the workspace field became license = "Apache-2.0" and the per-crate manifests point at it.

The guard moved twice, and ended as a script. A notice-check workflow job tested test -s NOTICE && grep -q "Leash project" NOTICE && grep -q "CC-BY" NOTICE && test -s LICENSE. When the workflows were dropped the same check became .github/scripts/notice-check.sh, so the guard survives without CI. This is the first entry, so it is also where the pattern of handing a check to a script instead of a runner starts.

The provenance gate kept being wrong, in four distinguishable ways. The verifier’s first version treated any byte-identical file as fatal, which flagged prose and rendered output that could not plausibly have been copied: provenance: a raw byte match is fatal unless the bytes are our own text (7751c45), then judge the reference on what it records, not what it renders (b2b4a70), then identity is fatal only for text this worktree authored (92e6871). None of those were kept as written. What was kept is text compared modulo line endings — compare text modulo line endings so the verdict ignores checkout settings (d99fe9a) — because a Windows checkout writes CRLF and the same file then reads as identical on one host and not on another. The final rule is in b7ac824 (#160): the identity verdict must not depend on checkout settings. The gate is also rooted at git rev-parse --show-toplevel rather than at the script’s own directory (902f286), so running the copy in a worktree measures that worktree and not main.

Secrets were a rule, not a review. .gitignore carries **/*.env, !**/*.env.example and deploy/**/camera-stream.env, so the one secret-shaped path in the private tree cannot be committed by accident. git check-ignore -v deploy/leash/camera-stream.env prints the match.

Two sources, one file

The NOTICE is where two other licences land, and neither of them is Apache-2.0:

• software from the Leash project (https://github.com/specdog/leash) under MIT;
• the Male CNS connectome (Berg et al. 2026, https://male-cns.janelia.org) under CC-BY 4.0.

So the repository’s licence is not one licence. Apache-2.0 covers the rewrite; MIT covers a dependency whose work is included; CC-BY covers data derived from a published dataset. The NOTICE is the join.

The clean-room boundary and the three attributions that cross into the repository. The dashed line is the decision: interfaces may be read, bytes may not be copied. The NOTICE is the only place the other two licences appear, and the guard keeps all three strings present.

The number the gate prints

The gate’s method is narrow on purpose: it compares only files whose relative path also exists in the reference checkout, because everything else cannot have been copied. That is why the compared count is smaller than the tracked count — 104 of 157, then 110 of 170.

Tracked, compared, identical — at the commit that introduced the check and at the head when it was last run. The third bar is zero at both. Drawn by the committed make_figures.py from provenance.json, not pasted.

Evidence

Quantity	Value	Unit	Source
First commit’s files	5	files	git show --stat 776bff0
Attribution blocks in NOTICE	3	blocks	NOTICE ^1
Workspace licence	Apache-2.0	—	Cargo.toml [workspace.package] ^1
Tracked files at 144bb6d	157	files	provenance.json ^2
Files compared at 144bb6d	104	files	same ^2
Byte-identical at 144bb6d	0	files	same ^2
Tracked files at a59b836	170	files	same ^2
Files compared at a59b836	110	files	same ^2
Byte-identical at a59b836	0	files	same ^2

^1 Read from the committed file at main, not from this text. ^2 docs/figures/the-licence-and-the-snapshot/provenance.json. The two runs were taken in a later session than the commits they measure; the commits are 144bb6d (which introduced the check) and a59b836 (the head then).

The commit range this entry describes is 776bff0..144bb6d — the snapshot and licence files through the commit that added the provenance gate. 776bff0 is the first commit on main; there is no history before it. A later run recorded in provenance.json is taken at a59b836. The rewrite itself is EPIC-00 (#66); this entry’s epic is EPIC-01 (#1).

What this does not establish

• Zero identical is measured against one checkout. The gate compares against the private reference tree present on the machine it runs on. A different revision of the reference, or none at all, gives a different number; the verdict is only as good as that checkout. The reference’s path is deliberately not recorded in the committed data.
• The comparison is byte equality, not similarity. A file that is 90 % copied is not identical and the gate passes it. Reformatting defeats the check; the check is a floor, not a proof of authorship.
• Two runs are recorded, not a continuous measurement. 144bb6d and a59b836 are the two runs in provenance.json. Nothing re-runs the gate on every commit.
• Not a legal opinion. That the NOTICE’s MIT and CC-BY attributions are the ones that are owed was decided by the plan’s step text, not by counsel; no third party audited the result.
• The 104/157 split is a path coincidence, not an audit. A file is compared only when a same-relative-path file exists in the reference; files that differ in name are never compared, so “0 identical” does not mean “0 files read”.