diff --git a/libc/include/bits/attrs.h b/libc/include/bits/attrs.h
index e8d28f34..c9f6cf58 100644
--- a/libc/include/bits/attrs.h
+++ b/libc/include/bits/attrs.h
@@ -1,3 +1,5 @@
+/* bits/attrs.h: Macros wrapping GCC attributes for use in the standard library. */
+
 #ifndef _BITS_ATTRS_H
 #define _BITS_ATTRS_H
 
diff --git a/libc/include/bits/clockid.h b/libc/include/bits/clockid.h
index 110886fb..f9827d6e 100644
--- a/libc/include/bits/clockid.h
+++ b/libc/include/bits/clockid.h
@@ -1,3 +1,5 @@
+/* bits/clockid.h: The clockid_t type and its supported values. */
+
 #ifndef _BITS_CLOCKID_H
 #define _BITS_CLOCKID_H
 
diff --git a/libc/include/bits/errno-return.h b/libc/include/bits/errno-return.h
index 2a147622..9d60c005 100644
--- a/libc/include/bits/errno-return.h
+++ b/libc/include/bits/errno-return.h
@@ -1,3 +1,5 @@
+/* bits/errno-return.h: Provides a convenient way of setting errno after a syscall. */
+
 #ifndef _BITS_ERRNO_RETURN_H
 #define _BITS_ERRNO_RETURN_H
 
diff --git a/libc/include/bits/timespec.h b/libc/include/bits/timespec.h
index c171d708..4b7afe42 100644
--- a/libc/include/bits/timespec.h
+++ b/libc/include/bits/timespec.h
@@ -1,3 +1,5 @@
+/* bits/timespec.h: Defines the timespec structure. */
+
 #ifndef _BITS_TIMESPEC_H
 #define _BITS_TIMESPEC_H
 
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index b7e75c17..683832f9 100644
--- a/libc/include/sys/syscall.h
+++ b/libc/include/sys/syscall.h
@@ -1,6 +1,9 @@
+/* sys/syscall.h: Defines syscall numbers. */
+
 #ifndef _SYS_SYSCALL_H
 #define _SYS_SYSCALL_H
 
+/* This header just forwards to luna/Syscall.h, which is used in the kernel as well. */
 #include <luna/Syscall.h>
 
 #endif
diff --git a/libc/include/sys/types.h b/libc/include/sys/types.h
index e4768a32..0f224f41 100644
--- a/libc/include/sys/types.h
+++ b/libc/include/sys/types.h
@@ -1,3 +1,5 @@
+/* sys/types.h: System data types. */
+
 #ifndef _SYS_TYPES_H
 #define _SYS_TYPES_H
 
diff --git a/libc/include/time.h b/libc/include/time.h
index 82eb7884..1698cd48 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -1,3 +1,5 @@
+/* time.h: Time management functions. */
+
 #ifndef _TIME_H
 #define _TIME_H