diff --git a/pdf.c b/pdf.c
index ff25e39df1125c6753dfbab596f4ceb1f6563dd7..b6e2089a4d77bd6376b50a97ccf1486352ed9435 100644
--- a/pdf.c
+++ b/pdf.c
@@ -262,6 +262,7 @@ act_a85group(const HParseResult *p, void *u)
 	HParsedToken **digits = h_seq_elements(p->ast);
 
 	/* 2^32-1, the max value the group can hold as per spec */
+	// XXX test with "s8W-!"
 	#define A85GRPMAX 4294967295
 
 	/* Only for groups that do not need to padded to 5 */