But that moves the burden of maintenance from the provider of the service to its users (and/or partially to intermediary in form of "skills registry" of sorts,

But that moves the burden of maintenance from the provider of the service to its users (and/or partially to intermediary in form of "skills registry" of sorts, which apparently is a thing now). So maybe a hybrid approach would make more sense? Something like /.well-known/skills/README.md exposed and owned by the providers? That is assuming that the whole idea of "skills" makes sense in practice.