Wcag Trend

Content-layer accessibility measures over time: latest snapshot per release version, chronologically (snapshots taken at each CDN publish).

Returns TWO SEPARATE series: points (current method: completeness + coverage) and, only with include_legacy=true, legacy_points (the retired "AA conformance score"). method_change_at marks the break. The two are never merged into one curve: the old formula counted presence checks as conformance, and the old points were deliberately NOT recomputed (a snapshot does not freeze its source content, so a recompute would be today's measure wearing a past date). With locale, the percentages are that locale's.