Following up from T330427: Add a way for skins and extensions to feed into "Installed client-side libraries" on Special:Version and T330508.
There should be a way to include a library in foreign-resources.yaml without it actually doing something. This would be useful for libraries which need a complex build step which ForeignResourceManager doesn't currently support, but we would still want to declare the dependency and show it in Special:Version. An example is d3 in GrowthExperiments.