diff --git a/libc/include/tar.h b/libc/include/tar.h
index a5d7a36..9d0c3ba 100644
--- a/libc/include/tar.h
+++ b/libc/include/tar.h
@@ -26,37 +26,64 @@
  * SUCH DAMAGE.
  */
 
-#ifndef _TAR_H_
-#define _TAR_H_
+#pragma once
+
+/**
+ * @file tar.h
+ * @brief Constants for reading/writing `.tar` files.
+ */
 
 #include <sys/cdefs.h>
 
+/** `.tar` file magic. (Includes the NUL.) */
 #define TMAGIC "ustar"
+/** `.tar` file magic length in bytes. */
 #define TMAGLEN 6
+/** `.tar` file version. (Does not include the NUL.) */
 #define TVERSION "00"
+/** `.tar` file version length in bytes. */
 #define TVERSLEN 2
 
+/** Regular file type flag. */
 #define REGTYPE '0'
+/** Alternate regular file type flag. */
 #define AREGTYPE '\0'
+/** Link type flag. */
 #define LNKTYPE '1'
+/** Symbolic link type flag. */
 #define SYMTYPE '2'
+/** Character special file type flag. */
 #define CHRTYPE '3'
+/** Block special file type flag. */
 #define BLKTYPE '4'
+/** Directory type flag. */
 #define DIRTYPE '5'
+/** FIFO special file type flag. */
 #define FIFOTYPE '6'
+/** Reserved type flag. */
 #define CONTTYPE '7'
 
+/** Set-UID mode field bit. */
 #define TSUID 04000
+/** Set-GID mode field bit. */
 #define TSGID 02000
+/** Directory restricted deletion mode field bit. */
 #define TSVTX 01000
+/** Readable by user mode field bit. */
 #define TUREAD 00400
+/** Writable by user mode field bit. */
 #define TUWRITE 00200
+/** Executable by user mode field bit. */
 #define TUEXEC 00100
+/** Readable by group mode field bit. */
 #define TGREAD 00040
+/** Writable by group mode field bit. */
 #define TGWRITE 00020
+/** Executable by group mode field bit. */
 #define TGEXEC 00010
+/** Readable by other mode field bit. */
 #define TOREAD 00004
+/** Writable by other mode field bit. */
 #define TOWRITE 00002
+/** Executable by other mode field bit. */
 #define TOEXEC 00001
-
-#endif /* _TAR_H_ */