The list element that is meant to hold the name of the directory to find "the goods" in seems to be in flux and the object that is generated within htmltools is not valid as far as rmarkdown is concerned.
htmltools::htmlDependency puts this in a list element named src and it seems that rmarkdown::validate_html_dependency expects this to be in a list element named path.
Furthermore, src is flagged as an invalid_field at the tail end rmarkdown::validate_html_dependency.
I'm running into this bug because I'm trying to get an rmdexmaples::datatable into an rmarkdown report.