diff --git a/core/wasm_shims/pythonplugin/python_plugin.cc b/core/wasm_shims/pythonplugin/python_plugin.cc
index d7850ed..2100e2e 100644
--- a/core/wasm_shims/pythonplugin/python_plugin.cc
+++ b/core/wasm_shims/pythonplugin/python_plugin.cc
@@ -3,6 +3,8 @@
 #include <cstdio>
 #include <cstdlib>
 
+// LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc provides the
+// native PythonPlugin implementation called by RS274 Python/remap paths.
 __attribute__((weak)) std::string handle_pyerror() {
     return "python disabled in wasm-safe probe";
 }
diff --git a/core/wasm_shims/pythonplugin/python_plugin.hh b/core/wasm_shims/pythonplugin/python_plugin.hh
index d36b8f1..c4bdd5b 100644
--- a/core/wasm_shims/pythonplugin/python_plugin.hh
+++ b/core/wasm_shims/pythonplugin/python_plugin.hh
@@ -8,6 +8,9 @@
 
 extern std::string handle_pyerror();
 
+// LinuxCNC source basis: src/emc/pythonplugin/python_plugin.hh declares this
+// status/API surface used by interp_python.cc, interp_namedparams.cc, and
+// rs274ngc_pre.cc.
 enum pp_status {
     PLUGIN_NO_SECTION = -1,
     PLUGIN_NO_INIFILE = -2,
@@ -57,4 +60,3 @@ private:
 };
 
 extern PythonPlugin *python_plugin;
-
diff --git a/linuxcnc-rs274-wasm-source-files.txt b/linuxcnc-rs274-wasm-source-files.txt
index c1a28f0..389a86f 100644
--- a/linuxcnc-rs274-wasm-source-files.txt
+++ b/linuxcnc-rs274-wasm-source-files.txt
@@ -51,6 +51,7 @@ header:src/emc/rs274ngc/rs274ngc.hh:LinuxCNC rs274 public interface header
 header:src/emc/rs274ngc/rs274ngc_interp.hh:LinuxCNC rs274 interpreter class header
 header:src/emc/rs274ngc/rs274ngc_return.hh:LinuxCNC rs274 return code header
 header:src/emc/rs274ngc/units.h:LinuxCNC rs274 units helper header
+header:src/emc/pythonplugin/python_plugin.hh:LinuxCNC PythonPlugin declarations used by wasm-safe Python plugin shim
 header:src/emc/ini/inifile.h:LinuxCNC C INI reader declarations exported by ini Submakefile
 header:src/emc/ini/inifile.hh:LinuxCNC C++ INI reader declarations used by inifile.cc
 header:src/emc/nml_intf/emc.hh:LinuxCNC EMC status declarations used by wasm-safe EMC status shim
@@ -63,6 +64,7 @@ header:src/rtapi/rtapi.h:LinuxCNC RTAPI snprintf declarations used by wasm-safe
 header:src/rtapi/rtapi_string.h:LinuxCNC RTAPI string helpers used by RS274 and RCS print sources
 metadata:src/emc/rs274ngc/Submakefile:LinuxCNC rs274 make build metadata tracked for full directory coverage
 metadata:src/emc/rs274ngc/meson.build:LinuxCNC rs274 meson build metadata tracked for full directory coverage
+metadata:src/emc/pythonplugin/python_plugin.cc:source basis for wasm-safe PythonPlugin shim
 metadata:src/emc/ini/Submakefile:LinuxCNC ini build metadata defining liblinuxcncini source and exported headers
 metadata:src/libnml/nml/stat_msg.cc:source basis for wasm-safe RCS_STAT_MSG constructor shim
 metadata:src/libnml/nml/nmlmsg.cc:source basis for wasm-safe NMLmsg constructor shim
diff --git a/test-linuxcnc-wasm-cmake-safe-probe.sh b/test-linuxcnc-wasm-cmake-safe-probe.sh
index 31fa1ab..bae2a32 100755
--- a/test-linuxcnc-wasm-cmake-safe-probe.sh
+++ b/test-linuxcnc-wasm-cmake-safe-probe.sh
@@ -906,6 +906,8 @@ dlfcn_shim=$(./list-linuxcnc-wasm-safe-shims.sh dlfcn.cc)
 grep -Fx "core/wasm_shims/dlfcn.cc" <<<"$dlfcn_shim" >/dev/null
 python_plugin_shim=$(./list-linuxcnc-wasm-safe-shims.sh python_plugin.cc)
 grep -Fx "core/wasm_shims/pythonplugin/python_plugin.cc" <<<"$python_plugin_shim" >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc provides the' core/wasm_shims/pythonplugin/python_plugin.cc >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/pythonplugin/python_plugin.hh declares this' core/wasm_shims/pythonplugin/python_plugin.hh >/dev/null
 python_c_api_shim=$(./list-linuxcnc-wasm-safe-shims.sh python_c_api_shim.cc)
 grep -Fx "core/wasm_shims/python_c_api_shim.cc" <<<"$python_c_api_shim" >/dev/null
 rtapi_compat_shim=$(./list-linuxcnc-wasm-safe-shims.sh rtapi_compat.cc)
diff --git a/test-native.sh b/test-native.sh
index e0e1866..7ee1d16 100755
--- a/test-native.sh
+++ b/test-native.sh
@@ -65,6 +65,8 @@ grep -F 'header:src/rtapi/rtapi_string.h:LinuxCNC RTAPI string helpers used by R
 grep -F 'metadata:src/rtapi/uspace_common.h:source basis for wasm-safe RTAPI snprintf compatibility shim' linuxcnc-rs274-wasm-source-files.txt >/dev/null
 grep -F 'header:include/hal.h:LinuxCNC HAL declarations used by wasm-safe runtime HAL lookup shim' linuxcnc-rs274-wasm-source-files.txt >/dev/null
 grep -F 'metadata:src/hal/hal_lib.c:source basis for wasm-safe runtime HAL lookup shim' linuxcnc-rs274-wasm-source-files.txt >/dev/null
+grep -F 'header:src/emc/pythonplugin/python_plugin.hh:LinuxCNC PythonPlugin declarations used by wasm-safe Python plugin shim' linuxcnc-rs274-wasm-source-files.txt >/dev/null
+grep -F 'metadata:src/emc/pythonplugin/python_plugin.cc:source basis for wasm-safe PythonPlugin shim' linuxcnc-rs274-wasm-source-files.txt >/dev/null
 grep -F 'metadata:src/emc/nml_intf/emcops.cc:source basis for native source-link EMC status constructor support object' linuxcnc-rs274-source-files.txt >/dev/null
 grep -F 'metadata:src/emc/sai/dummyemcstat.cc:source basis for native source-link emcStatus singleton support object' linuxcnc-rs274-source-files.txt >/dev/null
 grep -F 'metadata:src/emc/sai/Submakefile:LinuxCNC SAI build metadata defining dummyemcstat support object' linuxcnc-rs274-source-files.txt >/dev/null