I do not know the answer to this question.

Skyline external tools are .zip files. Inside of the .zip file is a folder called "tool-inf" which tells Skyline how to install the external tool.
In the QuaSAR zip file, it says that it needs R version 3.0.1.
Also, there is a file in there called "tool-inf/InstallPackages.r" which Skyline runs after installing R version 3.0.1.

When I try to install the QuaSAR external tool in Skyline, I see errors such as:

Warning: unable to access index for repository http://cran.us.r-project.org/bin/windows/contrib/3.0

   package 'bitops' is available as a source package but not as a binary

Warning message:
package 'bitops' is not available (for R version 3.0.1) 

This error comes from executing the line in "Install.Packages.r":

install.packages("bitops" , repos='http://cran.us.r-project.org')

It looks like the problem might be that the packages are no longer available from the r-project website because the version of R that QuaSAR wants to use is too old. I do not know what should be done about that if that is the case.

Maybe someone who is more of an expert on installing R could answer this. Maybe there would be some way to point to a different repository.
-- Nick

Editing of two files originally provided in QuaSAR-1_32 restored proper downloading and function in Skyline.
The QuaSAR.properties file was edited to call R, 4.0.0 instead of R, 3.0.1.
The install.packages file was changed by replacing "http:" with "https:" in the call to install packages from the cran site.
The corresponding new installation package (QuaSAR-2020.0) is provided here for vetting by the Skyline support team.

Happy 12th Anniversary to Skyline on this 1st day of the ASMS Reboot.