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1.9.3 review notes

Review boundary

This change implements only the active 1.9.3 complete-API-decision milestone. It classifies and documents the existing frozen 1.9 surface, resolves conventions and compatibility choices, checks common programs, and records the exact proposed 2.0 diff. It changes no src/ interface, storage layout, compiled default, numerical behavior, deprecation warning, or package content.

It does not implement numerical-validation, performance, portability, migration-rehearsal, beta, or final-freeze work planned after this milestone. The only newly requested capability—ergonomic 2-D and 3-D vector rotation—is routed to a focused 1.10.0 design and receives no 1.9.x declaration or invented public name.

Reviewable changes

1. Upgrade the exact 1.9 declaration snapshot to a decision-aware schema and classify every owner/signature row as recommended, advanced, compatibility, experimental, or generic implementation support. 2. Publish a 13-domain common-path map backed by existing concise, output-checked complete programs; fail the gate if a common program uses generic implementation support. 3. Resolve naming, indexing, shape, units, ownership, mutation, aliasing, exceptions, defaults, tolerances, outcomes, RNG state, cancellation, progress, and thread-safety conventions globally and for every domain. 4. Review all 21 plain compiler aliases against behavior, defaults, ownership, exception identity, and numerical results. Retain 17 and route the four pressure/velocity aliases to 1.9.7 migration/package-boundary confirmation without deprecating them. 5. Give all 131 compatibility rows exactly one decision: typed replacement plus semantic difference for matrix and pressure/velocity aliases, or explicit retention for the focused finance alias units. 6. Publish a machine-readable and human-readable exact proposed diff. Source, behavior, warning, and packaging lists are explicitly empty; documentary defaults are named separately. 7. Add selector, overload, generic-owner, exact-coverage, alias-review, common-example, convention, compatibility, and diff checks to release qualification.

Implementation discipline evidence

No public type or storage changes were made, so no ownership/layout change is being smuggled into a documentation release.
Documentation, generated reference data, checker behavior, and regression tests are reviewed together.
tools/update_api_snapshot.py remains the sole generator for the exact snapshot/reference and uses the reviewed decision manifest rather than hand-editing 2,880 generated rows.
Existing declarations remain until behavioral and compatibility evidence justifies a separately reviewed change; this release removes none.
Common-program review records an awkward missing operation as 1.10.0 design work instead of adding an unreviewed patch-release wrapper.

Completion-gate mapping

Gate	Mechanical evidence
No undecided stable declaration/alias/default/ownership/classification/replacement	`api-decision-2.0.json` has an empty unresolved list; `check_api_decision.py` reconstructs every classification, resolves all domains/concerns, requires exactly one review for every plain compiler alias, and requires exactly one decision for every compatibility row.
Every recommended common path has a concise checked example	The 13 manifest paths resolve to output-checked runnable fragments; documentation execution compiles/runs them and the decision checker rejects implementation-support names.
Exact source/behavior/warning/packaging consequences	`api-diff-1.9-to-2.0.json` contains all five required categories. The four compiled-impact categories are explicitly `no_change` with empty items; documentary changes are enumerated.
New capability routed to 1.10.0	2-D/3-D vector rotation is listed once in both decision and diff manifests with no proposed declaration; the checker requires matching 1.10.0 routes.

Before opening the PR

Regenerate the snapshot/reference and confirm a second generation produces no diff.
Run the decision/extractor unit tests, documentation structure checks, and compile/run every documentation fragment.
Run git diff --check, inspect that src/ has no diff, and review generated classification totals plus all 21 alias reviews and compatibility mappings.
Run the complete local 1.9.3 qualification, including normal/optimised/ checked-heap tests, examples, docs/site/offline archive, Lazarus package, and benchmark.
Push only after the candidate commit is clean; require the Linux and Windows checksummed clean-archive jobs to pass before tagging.