more comments

lib/internal/modules/run_main.js

@@ -9,7 +9,7 @@ const path = require('path');
 
 /**
  * Get the absolute path to the main entry point.
- * @param {string} main Entry point path
+ * @param {string} main - Entry point path
  */
 function resolveMainPath(main) {
   // Note extension resolution for the main entry point can be deprecated in a

lib/internal/process/pre_execution.js

@@ -176,12 +176,20 @@ function refreshRuntimeOptions() {
   refreshOptions();
 }
 
+/**
+ * Patch the process object with legacy properties and normalizations.
+ * Replace `process.argv[0]` with `process.execPath`, preserving the original `argv[0]` value as `process.argv0`.
+ * Replace `process.argv[1]` with the resolved absolute file path of the entry point, if found.
+ * @param {boolean} expandArgv1 - Whether to replace `process.argv[1]` with the resolved absolute file path of
+ * the main entry point.
+ */
 function patchProcessObject(expandArgv1) {
   const binding = internalBinding('process_methods');
   binding.patchProcessObject(process);
 
   require('internal/process/per_thread').refreshHrtimeBuffer();
 
+  // Since we replace process.argv[0] below, preserve the original value in case the user needs it.
   ObjectDefineProperty(process, 'argv0', {
     __proto__: null,
     enumerable: true,
@@ -194,6 +202,8 @@ function patchProcessObject(expandArgv1) {
   process._exiting = false;
   process.argv[0] = process.execPath;
 
+  // If requested, update process.argv[1] to replace whatever the user provided with the resolved absolute file path of
+  // the entry point.
   if (expandArgv1 && process.argv[1] &&
       !StringPrototypeStartsWith(process.argv[1], '-')) {
     // Expand process.argv[1] into a full path.