Confused on how to access packages in webr-0.4.0/vfs/usr/lib/R/library folder when hosting webR on local server

[SugarRayLua]

Recently trying out self-hosting webR on local server on mobile device (iOS iPad).

Downloaded releases version of webR and hosting on iOS iPad local server app by then opening webr-0.4.0 folder on the local server and pointing the server to index.html. WebR works great by that process and am able to install and use packages from the webR repository.

However, as per many other requests that have been posted, I'm interested in having my most commonly used R packages persist on my device instead of needing to download every time I open up my local server and browser and am more limited by mobile device sandboxing. I noticed that the webr-0.4.0 release that I downloaded includes a library folder:

webr-0.4.0/vfs/usr/lib/R/library

with what appeared to be the webR libraries that are standardly loaded when webR starts, and I presumed that webR loaded its libraries into the virtual FS by loading the libraries in the above folder. If so, I figured I could just download additional webR packaged libraries and add them to the above library folder and then webR would load with the additional packages preconfigured when I start webR. However, that doesn't occur-- despite having a webR package in the above folder on my local server (e.g. cli) it doesn't show up in the virtual FS for me to use when I start webR.

What then are the packages in the above library of the release version of webR for self-hosting used for? Would it be possible to point webR to that folder so that I can add additional libraries to it that would be automatically mounted to the VFS when webR loads on my local hosted server?

thanks!