When I use a HTML template for Rmarkdown,
(e.g., one of the samples HERE),
how much am I allowed to modify these templates??
Is it okay to modify all the way through it (.css files and so on)?
Also, what is the appropriate way to acknowledge the use of the template for the provider?
Good question. At least some of the non-RStudio templates have a GitHub repository without a LICENSE file. As for the RStudio templates maybe this article is viewed by an RStudio employee, who can answer this.