You'll notice
Useful2 Signal1
Undefined spacing values now unset rather than snapping to zero, so some layouts may shift slightly.
What's wrong with this entry?
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What
The layout engine no longer coerces an undefined margin or padding to 0, so passing undefined now unsets the value rather than pinning it. Spacing may shift slightly in components that compute those values conditionally.
Evidence
setMarginAuto
Strings lifted out of the shipped bundle, so the claim above can be checked against them.