diff --git a/core/wasm_shims/dlfcn.cc b/core/wasm_shims/dlfcn.cc
index d9fbf25..037c1c8 100644
--- a/core/wasm_shims/dlfcn.cc
+++ b/core/wasm_shims/dlfcn.cc
@@ -2,6 +2,8 @@
 
 #include <cstring>
 
+// LinuxCNC source basis: src/emc/rs274ngc/interp_base.cc uses dlopen(),
+// dlsym(), dlerror(), RTLD_GLOBAL, and RTLD_NOW for native interpreter loading.
 namespace {
 
 thread_local char last_error[128] = "dynamic loading is unavailable in wasm-safe probe";
@@ -27,4 +29,3 @@ int dlclose(void *) {
 }
 
 } // extern "C"
-
diff --git a/core/wasm_shims/dlfcn.h b/core/wasm_shims/dlfcn.h
index 99185ed..da9740a 100644
--- a/core/wasm_shims/dlfcn.h
+++ b/core/wasm_shims/dlfcn.h
@@ -4,6 +4,7 @@
 extern "C" {
 #endif
 
+/* LinuxCNC source basis: src/emc/rs274ngc/interp_base.cc native loader flags. */
 #define RTLD_GLOBAL 0x00100
 #define RTLD_NOW 0x00002
 
@@ -15,4 +16,3 @@ int dlclose(void *handle);
 #ifdef __cplusplus
 }
 #endif
-
diff --git a/test-linuxcnc-wasm-cmake-safe-probe.sh b/test-linuxcnc-wasm-cmake-safe-probe.sh
index 61fb757..79784df 100755
--- a/test-linuxcnc-wasm-cmake-safe-probe.sh
+++ b/test-linuxcnc-wasm-cmake-safe-probe.sh
@@ -1409,6 +1409,8 @@ grep -F 'noncopyable(const noncopyable &) = delete;' core/wasm_shims/boost/nonco
 test -f core/wasm_shims/libgen.h
 grep -F 'inline char *basename(const char *path)' core/wasm_shims/libgen.h >/dev/null
 grep -F 'return basename(const_cast<char *>(path));' core/wasm_shims/libgen.h >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/rs274ngc/interp_base.cc uses dlopen(),' core/wasm_shims/dlfcn.cc >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/rs274ngc/interp_base.cc native loader flags.' core/wasm_shims/dlfcn.h >/dev/null
 grep -F 'extern "C" int wordexp(const char *words, wordexp_t *pwordexp, int)' core/wasm_shims/linuxcnc_runtime_shim.cc >/dev/null
 grep -F 'extern "C" void wordfree(wordexp_t *pwordexp)' core/wasm_shims/linuxcnc_runtime_shim.cc >/dev/null
 grep -F 'EMC_STAT *emcStatus = new EMC_STAT;' core/wasm_shims/emc_status_shim.cc >/dev/null