diff --git a/src/d_netfil.c b/src/d_netfil.c
index 989d20db..a321fb78 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -130,6 +130,7 @@ UINT8 *PutFileNeeded(UINT16 firstfile)
 
 		nameonly(strcpy(wadfilename, wadfiles[i]->filename));
 
+		// Look below at the WRITE macros to understand what these numbers mean.
 		if (p + 1 + 4 + strlen(wadfilename) + 1 + 16 > p_start + MAXFILENEEDED)
 		{
 			// Too many files to send all at once