diff --git a/sys/amd64/linux/syscalls.master b/sys/amd64/linux/syscalls.master
index 90476b15433f..a2ac67c2d126 100644
--- a/sys/amd64/linux/syscalls.master
+++ b/sys/amd64/linux/syscalls.master
@@ -26,6 +26,10 @@
 ;		function prototype in sys/sysproto.h.  Does add a
 ;		definition to syscall.h besides adding a sysent.
 
+; #include's, #defines's, etc. may be included, and are copied to the output
+; files. However, #ifdef, etc will be copied, but any lines that don't start
+; with # will not. Caveat Emptor.
+
 #include <sys/param.h>
 #include <sys/sysent.h>
 #include <sys/sysproto.h>
@@ -36,8 +40,6 @@
 ; Isn't pretty, but there seems to be no other way to trap nosys
 #define	nosys	linux_nosys
 
-; #ifdef's, etc. may be included, and are copied to the output files.
-
 0	AUE_NULL	NOPROTO {
 		int read(
 		    int fd,
diff --git a/sys/amd64/linux32/syscalls.master b/sys/amd64/linux32/syscalls.master
index 4561667dc3cc..f84d51c372a8 100644
--- a/sys/amd64/linux32/syscalls.master
+++ b/sys/amd64/linux32/syscalls.master
@@ -26,6 +26,10 @@
 ;		function prototype in sys/sysproto.h.  Does add a
 ;		definition to syscall.h besides adding a sysent.
 
+; #include's, #defines's, etc. may be included, and are copied to the output
+; files. However, #ifdef, etc will be copied, but any lines that don't start
+; with # will not. Caveat Emptor.
+
 #include <sys/param.h>
 #include <sys/sysent.h>
 #include <sys/sysproto.h>
@@ -36,8 +40,6 @@
 ; Isn't pretty, but there seems to be no other way to trap nosys
 #define	nosys	linux_nosys
 
-; #ifdef's, etc. may be included, and are copied to the output files.
-
 0	AUE_NULL	UNIMPL	setup
 1	AUE_EXIT	STD {
 		void linux_exit(
diff --git a/sys/arm64/linux/syscalls.master b/sys/arm64/linux/syscalls.master
index 647fd0262e8c..f4c2acca435d 100644
--- a/sys/arm64/linux/syscalls.master
+++ b/sys/arm64/linux/syscalls.master
@@ -3,6 +3,10 @@
 ; Linux ABI system call generic name/number map, based on Linux file
 ; include/uapi/asm-generic/unistd.h
 
+; #include's, #defines's, etc. may be included, and are copied to the output
+; files. However, #ifdef, etc will be copied, but any lines that don't start
+; with # will not. Caveat Emptor.
+
 #include <sys/param.h>
 #include <sys/sysent.h>
 #include <sys/sysproto.h>
diff --git a/sys/i386/linux/syscalls.master b/sys/i386/linux/syscalls.master
index a5b246c0822a..96b74e1cc649 100644
--- a/sys/i386/linux/syscalls.master
+++ b/sys/i386/linux/syscalls.master
@@ -26,6 +26,10 @@
 ;		function prototype in sys/sysproto.h.  Does add a
 ;		definition to syscall.h besides adding a sysent.
 
+; #include's, #defines's, etc. may be included, and are copied to the output
+; files. However, #ifdef, etc will be copied, but any lines that don't start
+; with # will not. Caveat Emptor.
+
 #include <sys/param.h>
 #include <sys/sysent.h>
 #include <sys/sysproto.h>
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 92de51fc0d97..af2f4194e2c5 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -108,7 +108,9 @@
 ;	timet_	Object contains a time_t and varies between i386 and other
 ;		ABIs.
 
-; #ifdef's, etc. may be included, and are copied to the output files.
+; #include's, #defines's, etc. may be included, and are copied to the output
+; files. However, #ifdef, etc will be copied, but any lines that don't start
+; with # will not. Caveat Emptor.
 
 #include <sys/param.h>
 #include <sys/sysent.h>