Standby database only available on Enterprise Edition?

Looking at the Database edition comparison chart, I see DataGuard is only available as part of Enterprise Edition.

Does this mean that standby databases are not available on Standard or Standard One licences? Or is there some lesser form of standby database which is available in standard edition.

(I know the software is the same, and you can't install DataGuard as an item, but I'm talking legally rather than technically.)

TIA

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Jim Smith
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