Hey,
Thanks for your replies. I had to adapt the paths a bit, I hope these are the files that you were looking for:
> readLines("C:/Program Files/R/R-4.1.0/src/library/windlgs/src/Makevars.win")
[1] "PKG_LIBS=$(GRAPHAPP_LIB)"
> readLines("C:/Program Files/R/R-4.1.0/library/base/help/Renviron.html")
[1] "<html><head><meta http-equiv='refresh' content='0; url=../html/Startup.html'></head></html>"
> readLines("C:/Program Files/R/R-4.1.0/library/base/R/Rprofile")
[1] "### This is the system Rprofile file. It is always run on startup."
[2] "### Additional commands can be placed in site or user Rprofile files"
[3] "### (see ?Rprofile)."
[4] ""
[5] "### Copyright (C) 1995-2020 The R Core Team"
[6] ""
[7] "### Notice that it is a bad idea to use this file as a template for"
[8] "### personal startup files, since things will be executed twice and in"
[9] "### the wrong environment (user profiles are run in .GlobalEnv)."
[10] ""
[11] ".GlobalEnv <- globalenv()"
[12] "attach(NULL, name = \"Autoloads\")"
[13] ".AutoloadEnv <- as.environment(2)"
[14] "assign(\".Autoloaded\", NULL, envir = .AutoloadEnv)"
[15] "T <- TRUE"
[16] "F <- FALSE"
[17] "R.version <- structure(R.Version(), class = \"simple.list\")"
[18] "version <- R.version # for S compatibility"
[19] ""
[20] "## for backwards compatibility only"
[21] "R.version.string <- R.version$version.string"
[22] ""
[23] "## NOTA BENE: options() for non-base package functionality are in places like"
[24] "## --------- ../utils/R/zzz.R"
[25] ""
[26] "options(keep.source = interactive())"
[27] "options(warn = 0)"
[28] "# options(repos = c(CRAN=\"@CRAN@\"))"
[29] "# options(BIOC = \"http://www.bioconductor.org\")"
[30] ""
[31] "## setting from an env variable added in 4.0.2"
[32] "local({to <- as.integer(Sys.getenv(\"R_DEFAULT_INTERNET_TIMEOUT\", 60))"
[33] " if (is.na(to) || to <= 0) to <- 60L"
[34] " options(timeout = to)"
[35] "})"
[36] "options(encoding = \"native.enc\")"
[37] "options(show.error.messages = TRUE)"
[38] "## keep in sync with PrintDefaults() in ../../main/print.c :"
[39] "options(scipen = 0)"
[40] "options(max.print = 99999)# max. #{entries} in internal printMatrix()"
[41] "options(add.smooth = TRUE)# currently only used in 'plot.lm'"
[42] ""
[43] "if(isFALSE(as.logical(Sys.getenv(\"_R_OPTIONS_STRINGS_AS_FACTORS_\","
[44] " \"FALSE\")))) {"
[45] " options(stringsAsFactors = FALSE)"
[46] "} else {"
[47] " options(stringsAsFactors = TRUE)"
[48] "}"
[49] ""
[50] "if(!interactive() && is.null(getOption(\"showErrorCalls\")))"
[51] " options(showErrorCalls = TRUE)"
[52] ""
[53] "local({dp <- Sys.getenv(\"R_DEFAULT_PACKAGES\")"
[54] " if(identical(dp, \"\")) ## it fact methods is done first"
[55] " dp <- c(\"datasets\", \"utils\", \"grDevices\", \"graphics\","
[56] " \"stats\", \"methods\")"
[57] " else if(identical(dp, \"NULL\")) dp <- character(0)"
[58] " else dp <- strsplit(dp, \",\")[[1]]"
[59] " dp <- sub(\"[[:blank:]]*([[:alnum:]]+)\", \"\\\\1\", dp) # strip whitespace"
[60] " options(defaultPackages = dp)"
[61] " })"
[62] ""
[63] "## Expand R_LIBS_* environment variables."
[64] "Sys.setenv(R_LIBS_SITE ="
[65] " .expand_R_libs_env_var(Sys.getenv(\"R_LIBS_SITE\")))"
[66] "Sys.setenv(R_LIBS_USER ="
[67] " .expand_R_libs_env_var(Sys.getenv(\"R_LIBS_USER\")))"
[68] ""
[69] "local({"
[70] " if(nzchar(tl <- Sys.getenv(\"R_SESSION_TIME_LIMIT_CPU\")))"
[71] " setSessionTimeLimit(cpu = tl)"
[72] " if(nzchar(tl <- Sys.getenv(\"R_SESSION_TIME_LIMIT_ELAPSED\")))"
[73] " setSessionTimeLimit(elapsed = tl)"
[74] "})"
[75] ""
[76] ".First.sys <- function()"
[77] "{"
[78] " for(pkg in getOption(\"defaultPackages\")) {"
[79] " res <- require(pkg, quietly = TRUE, warn.conflicts = FALSE,"
[80] " character.only = TRUE)"
[81] " if(!res)"
[82] " warning(gettextf('package %s in options(\"defaultPackages\") was not found', sQuote(pkg)),"
[83] " call. = FALSE, domain = NA)"
[84] " }"
[85] "}"
[86] ""
[87] "## called at C level in the startup process prior to .First.sys"
[88] ".OptRequireMethods <- function()"
[89] "{"
[90] " pkg <- \"methods\" # done this way to avoid R CMD check warning"
[91] " if(pkg %in% getOption(\"defaultPackages\"))"
[92] " if(!require(pkg, quietly = TRUE, warn.conflicts = FALSE,"
[93] " character.only = TRUE))"
[94] " warning('package \"methods\" in options(\"defaultPackages\") was not found',"
[95] " call. = FALSE)"
[96] "}"
[97] ""
[98] "if(nzchar(Sys.getenv(\"R_BATCH\"))) {"
[99] " .Last.sys <- function()"
[100] " {"
[101] " cat(\"> proc.time()\\n\")"
[102] " print(proc.time())"
[103] " }"
[104] " ## avoid passing on to spawned R processes"
[105] " ## A system has been reported without Sys.unsetenv, so try this"
[106] " try(Sys.setenv(R_BATCH=\"\"))"
[107] "}"
[108] ""
[109] "local({"
[110] " if(nzchar(rv <- Sys.getenv(\"_R_RNG_VERSION_\")))"
[111] " suppressWarnings(RNGversion(rv))"
[112] "})"
[113] ""
[114] ".sys.timezone <- NA_character_"
[115] "###-*- R -*-"
[116] ""
[117] "## this will break if R is on a network share"
[118] ".Library <- file.path(chartr(\"\\\\\", \"/\", R.home()), \"library\")"
[119] ".Library.site <- Sys.getenv(\"R_LIBS_SITE\")"
[120] ".Library.site <- if(!nzchar(.Library.site)) file.path(R.home(), \"site-library\") else unlist(strsplit(.Library.site, \";\"))"
[121] ".Library.site <- .Library.site[file.exists(.Library.site)]"
[122] ""
[123] "if(!nzchar(Sys.getenv(\"R_LIBS_USER\")))"
[124] " Sys.setenv(R_LIBS_USER="
[125] " file.path(Sys.getenv(\"R_USER\"), \"R\","
[126] " \"win-library\","
[127] " paste(R.version$major,"
[128] " sub(\"\\\\..*$\", \"\", R.version$minor),"
[129] " sep=\".\")"
[130] " ))"
[131] ""
[132] "invisible(.libPaths(c(unlist(strsplit(Sys.getenv(\"R_LIBS\"), \";\")),"
[133] " unlist(strsplit(Sys.getenv(\"R_LIBS_USER\"), \";\"))"
[134] " )))"
[135] ""
[136] "local({"
[137] " popath <- Sys.getenv(\"R_TRANSLATIONS\", \"\")"
[138] " if(!nzchar(popath)) {"
[139] " paths <- file.path(.libPaths(), \"translations\", \"DESCRIPTION\")"
[140] " popath <- dirname(paths[file.exists(paths)][1])"
[141] " }"
[142] " bindtextdomain(\"R\", popath)"
[143] " bindtextdomain(\"R-base\", popath)"
[144] " bindtextdomain(\"RGui\", popath)"
[145] " assign(\".popath\", popath, .BaseNamespaceEnv)"
[146] "})"
[147] ""
[148] "if(nzchar(Sys.getenv(\"R_PAPERSIZE\"))) {"
[149] " options(papersize = Sys.getenv(\"R_PAPERSIZE\"))"
[150] "} else {"
[151] " if(grepl(\"(canada|united.states)\", Sys.getlocale(\"LC_MONETARY\"),"
[152] " ignore.case = TRUE)) options(papersize = \"letter\")"
[153] " else options(papersize = \"a4\")"
[154] "}"
[155] ""
[156] "options(pager = if(length(grep(\"--ess\", commandArgs()))) \"console\" else \"internal\","
[157] " useFancyQuotes = (.Platform$GUI == \"Rgui\"),"
[158] " pdfviewer = Sys.getenv(\"R_PDFVIEWER\", file.path(R.home(\"bin\"), \"open.exe\")))"
[159] ""
[160] "if(.Platform$GUI == \"Rgui\")"
[161] " Sys.setenv(GFORTRAN_STDOUT_UNIT = \"-1\", GFORTRAN_STDERR_UNIT = \"-1\")"
[162] ""
[163] "local({"
[164] " br <- Sys.getenv(\"R_BROWSER\", NA_character_)"
[165] " if(!is.na(br)) options(browser = br)"
[166] " tests_startup <- Sys.getenv(\"R_TESTS\")"
[167] " if(nzchar(tests_startup)) source(tests_startup)"
[168] " ca_cert <- Sys.getenv(\"CURL_CA_BUNDLE\", NA_character_)"
[169] " if(!is.na(ca_cert) &&"
[170] " file.exists(ca_path <- file.path(R.home(\"etc\"), \"curl-ca-bundle.crt\")))"
[171] " Sys.setenv(CURL_CA_BUNDLE = ca_path)"
[172] "})"
> readLines("C:/Program Files/R/R-4.1.0/src/library/windlgs/src/Makevars.win")
[1] "PKG_LIBS=$(GRAPHAPP_LIB)"
> Sys.getenv("PATH")
[1] "C:\\Program Files\\R\\R-4.1.0\\bin\\x64;C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\;C:\\Windows\\System32\\OpenSSH\\;C:\\Program Files\\NVIDIA Corporation\\NVIDIA NvDLISR;C:\\Program Files (x86)\\NVIDIA Corporation\\PhysX\\Common;C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem;C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0\\;C:\\WINDOWS\\System32\\OpenSSH\\;C:\\Program Files\\MATLAB\\R2020b\\bin;C:\\Users\\Oswin\\AppData\\Local\\Programs\\Python\\Python39;C:\\Users\\Oswin\\AppData\\Local\\Programs\\Julia-1.6.1\\bin;C:\\Users\\Oswin\\AppData\\Local\\Programs\\Python\\Python39\\Scripts;C:\\Program Files\\dotnet\\;C:\\Program Files\\Docker\\Docker\\resources\\bin;C:\\ProgramData\\DockerDesktop\\version-bin;C:\\Users\\Oswin\\AppData\\Local\\Microsoft\\WindowsApps;C:\\Users\\Oswin\\AppData\\Roaming\\Python\\Python38\\Scripts;C:\\Users\\Oswin\\AppData\\Roaming\\Python\\Python38\\site-packages;C:\\Users\\Oswin\\AppData\\Local\\Programs\\MiKTeX\\miktex\\bin\\x64\\;C:\\Program Files\\Inkscape\\bin;;C:\\Program Files\\JetBrains\\PyCharm Community Edition 2021.1.2\\bin;"
> Sys.getenv("RTOOLS40_HOME")
[1] "C:\\Program Files\\rtools40"