Especially with damLinkField and external providers it gets tricky to be able copy the link values.
The fields hold Asset objects and even with textInputAllowed, user would see only the (jcr:UUID) pattern.

The idea is to implement a clipboard

A] Buttons on the link field
might requires complex UX patterns
button should update enabled status based on status of the clipboard (requires a reactive observable context, all fields immediately reacts on copy in an other field, )
easy to spot and understand

B] CTRL/META+C, CTRL/META+V shortcuts
minimal UX design
as the shortcut listens to whole form, the implementation would work for other fields as well (combo, radio...)
requires significant docu, as the presence of the feature is not obvious

C] Context menu in the link field
minimal UX design
requires docu, as the presence of the feature is not obvious