Generate SBOM of .kcm files in layoutlib.

Bug: 303905932
Test: CIs; m layoutlib dist
Change-Id: Iab35c44bdfff7ea82734a8efd37dfa005bae2664
diff --git a/tools/sbom/generate-sbom-framework_res.py b/tools/sbom/generate-sbom-framework_res.py
index d6be734..e637d53 100644
--- a/tools/sbom/generate-sbom-framework_res.py
+++ b/tools/sbom/generate-sbom-framework_res.py
@@ -20,6 +20,13 @@
 import sbom_data
 import sbom_writers
 
+'''
+This script generates SBOM of framework_res.jar of layoutlib shipped with Android Studio.
+
+The generated SBOM contains some placeholders which should be substituted by release_layoutlib.sh.
+The placeholders include: document name, document namespace, organization, created timestamp and 
+the SHA1 checksum of framework_res.jar.
+'''
 
 def get_args():
   parser = argparse.ArgumentParser()