They're initially prefixed because the standard is not finished. Many of them are _still_ prefixed because WebKit has a policy of never removing prefixed featu

They're initially prefixed because the standard is not finished. Many of them are _still_ prefixed because WebKit has a policy of never removing prefixed features, even if they implement the unprefixed one. So people feel no compunction about using the prefixed stuff in production, and since they only test in WebKit they don't notice when they're using the -webkit-prefixed version even though every single browser (or every browser except WebKit, in some cases) supports the unprefixed standard version.