diff --git a/llvm/tools/llvm-remarkutil/RemarkFilter.cpp b/llvm/tools/llvm-remarkutil/RemarkFilter.cpp
index acfef6608677c..507ae36f4a594 100644
--- a/llvm/tools/llvm-remarkutil/RemarkFilter.cpp
+++ b/llvm/tools/llvm-remarkutil/RemarkFilter.cpp
@@ -20,7 +20,9 @@ using namespace llvm;
 using namespace remarks;
 using namespace llvm::remarkutil;
 
-namespace filter {
+// Note: Avoid using the identifier "filter" in this file, as it is prone to
+// namespace collision with headers that might get included e.g.
+// curses.h.
 
 static cl::SubCommand FilterSub("filter",
                                 "Filter remarks based on specified criteria.");
@@ -80,5 +82,3 @@ static Error tryFilter() {
 }
 
 static CommandRegistration FilterReg(&FilterSub, tryFilter);
-
-} // namespace filter