implementation of OpenXR 1.1 Spatial Anchors - XR_EXT_spatial_anchor

Due to a lack of meta support for the metaXR plugin, I’m exploring switching to openXR.

Unreal 5.7 implements Foveated Rendering and Passthrough, but I need anchor support as well.

What headsets implement XR_EXT_spatial_anchor?

Is there any planned support for this in unreal, or would anyone be interested in writing a plugin to support this?