install.R vs DESCRIPTION

[rgaiacs]

The "Configuration for research and data science workflows" page says

install.R - Install packages with R/RStudio

This is used to install R libraries pinned to a specific snapshot on Posit Package Manager.

[...]

DESCRIPTION - Install an R package

Where YYYY-MM-DD is a snapshot of CRAN that will be used for your R installation.

Why cannot both use Posit Package Manager?

[manics]

I think in both cases CRAN packages are installed via Posit Package Manager

repo2docker/repo2docker/buildpacks/r.py

Lines 19 to 45 in 6cf91e4

	Setup R for use with a repository
	This sets up R + RStudio + IRKernel for a repository that contains:
	1. A `runtime.txt` file with the text:
	r-<year>-<month>-<date>
	Where 'year', 'month' and 'date' refer to a specific
	date whose CRAN snapshot we will use to fetch packages.
	Uses https://packagemanager.posit.co.
	2. A `DESCRIPTION` file signaling an R package
	If there is no `runtime.txt`, then the CRAN snapshot is set to latest
	date that is guaranteed to exist across timezones.
	Additional R packages are installed if specified either
	- in a file `install.R`, that will be executed at build time,
	and can be used for installing packages from both CRAN and GitHub
	- as dependencies in a `DESCRIPTION` file
	- are needed by a specific tool
	R is installed from https://docs.rstudio.com/resources/install-r/

I can see why it's confusing though, so it'd be good to make the language consistent.