When initializing the rpy2 R environment, JMP first uses the R_HOME environment variable to try and find R.
If R is not found, JMP tries other ways to find R. On Windows, the registry is searched, and on Apple macOS, /Library/Frameworks/R.framework is searched.
If R_HOME is not set, R.py in the jmpex package executes the following:
#Set the R_HOME environment variable so JMP knows where
#to find the local R installation.
if platform.system() == 'Windows':
os.environ['R_HOME'] = 'C:/Program Files/R/R-4.3.1'
else:
os.environ['R_HOME']='/Library/Frameworks/R.framework/Versions/Current/Resources'
On Apple MacOS, JMP uses the value of the R_HOME environment variable if the variable exists. Otherwise, it looks in:
/Library/Frameworks/R.framework/Versions/Current/Resources