diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.cpp b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
index 8e9eac9..b73f971 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.cpp
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
@@ -241,6 +241,8 @@
 
   // Don't include trailing NUL.
   pBuff.resize(nActualLen - 1);
+
+  // Use FromDefANSI() per "local encoding" comment in fpdf_formfill.h.
   return WideString::FromDefANSI(ByteStringView(pBuff));
 }
 
@@ -314,6 +316,8 @@
 
   // Don't include trailing NUL.
   pBuff.resize(nActualLen - 1);
+
+  // Use FromDefANSI() per "local encoding" comment in fpdf_formfill.h.
   return WideString::FromDefANSI(ByteStringView(pBuff));
 }