How do I include my .pptx or .potx in my R package?

I am working on a package in R for my company. I want a package that is able to generate reports in the company style. I have a .Rmd file to generate some PDF reports, and some LaTeX .sty files. These are all stored in /inst/latex_files/ and /inst/rmd/ based on some answers I found online. I call these files via

system.file("latex_files", "style.sty", package = "my_r_package")

I have done this similarly for my .pptx file, but now from devtools::check() I get the following result:

❯ checking for portable file names ... WARNING
  Found the following file with a non-portable file name:
    inst/pptx_files/template.potx
  These are not fully portable file names.
  See section ‘Package structure’ in the ‘Writing R Extensions’ manual.

Is there a way to include this? The only Package structure in Writing R Extensions manual I know is here, but this does not seem to tackle file types.