diff --git a/scripts/klippy-requirements.txt b/scripts/klippy-requirements.txt
index a25eaa34..5c215e2c 100644
--- a/scripts/klippy-requirements.txt
+++ b/scripts/klippy-requirements.txt
@@ -2,12 +2,19 @@
 # the Klipper host software (Klippy).  These package requirements are
 # typically installed via the command:
 #   pip install -r klippy-requirements.txt
+
+# The 'cffi' package is used by the "chelper" code
 cffi==1.14.6
-pyserial==3.4
+# greenlet is used by the reactor.py code
 greenlet==2.0.2 ; python_version < '3.12'
 greenlet==3.0.3 ; python_version >= '3.12'
+# Jinja2 is used by gcode_macro.py
 Jinja2==2.11.3
+markupsafe==1.1.1       # Needed by Jinja2
+# pyserial is used by serialhdl.py (for USB and UART mcu connections)
+pyserial==3.4
+# python-can is used by serialhdl.py (for canbus mcu connections)
 python-can==3.3.4
-markupsafe==1.1.1
 setuptools==75.6.0 ; python_version >= '3.12' # Needed by python-can
+# msgspec is an optional dependency of webhooks.py
 msgspec==0.19.0 ; python_version >= '3.9'