The template with every recognised placeholder replaced.
True when a placeholder the template actually REFERENCES resolved to an empty string.
The tooltip ignores this (it renders the gap and is gated separately on
having any content at all), but link and copy must not: a template
like https://uniprot.org/{hover_label} with no label yields
https://uniprot.org/, which is a plausible-looking URL pointing at the
wrong place. Suppressing beats navigating somewhere unintended.
This is not hypothetical. Under substitutive_lod= the Python adders copy
every non-compositing attr onto the COARSE children as well as the finest
(core/group/adders/points.py, child_attrs / gsplat_child_attrs), and
those coarse levels are synthesised gsplats that carry no labels at all —
so a labelled layer with a link is guaranteed to hover label-less elements
at coarse LOD.
Result of a substitution pass.