Asset Share is not available anymore, but a new reference implementation is available as open source project on Package Share.
Is this in reference to the "share asset" function here: Asset link sharing or is it referencing asset share pages? The Package Share link referenced in the "Note" points to the old Geometrixx sample sites files.
Both Asset link Share and Asset Share pages work on our 6.3 instance and are used. What exactly does "Asset Share is not available anymore" really mean?
It was part of sample content of Geometrixx which is still available and you can download from Package Share. Since we did not shipped that with 6.3; more info here We.Retail Reference Implementation so you need to install that to review sample implementation.