R help - Sep 2022 - Why R >= 4.1 warns about installing Rtools on Windows?

Hi,

Martin M. helped me focussing the context of my question.? The main 
result of my trials (various R4.x installations) after his mail is that 
the warning is issued when using *devtools* to install a package *from 
github*. When installing a package with install.packages(), no warning.

The warning looks like:

devtools::install_github("i-cyto/cytoBatchNorm")
WARNING: Rtools is required to build R packages, but no version of 
Rtools compatible with R 4.2.1 was found. (Only the following 
incompatible version(s) of Rtools were found: 4.0)
Please download and install Rtools 4.2 from 
https://cran.r-project.org/bin/windows/Rtools/ or 
https://www.r-project.org/nosvn/winutf8/ucrt3/.
Downloading GitHub repo i-cyto/cytoBatchNorm at HEAD
...

I don't think there is a need of Rtools. Let me know if you think there 
is a need of Rtools being installed prior to installing a pure R 
package. From your answers, I may contact the maintainer of devtools.

Thanks for reading.

Bonne journ?e,
Samuel