MySQL源代码中的tags文件主要是起什么作用？？

以下是部分内容！：
!_TAG_FILE_FORMAT 2 /extended format; --format=1 will not append ;" to lines/
!_TAG_FILE_SORTED 1 /0=unsorted, 1=sorted, 2=foldcase/
!_TAG_PROGRAM_AUTHOR Darren Hiebert /[email protected]/
!_TAG_PROGRAM_NAME Exuberant Ctags //
!_TAG_PROGRAM_URL http://ctags.sourceforge.net /official site/
!_TAG_PROGRAM_VERSION 5.5.2 //
ACQUIRE ../btree/bt_cursor.c 58;" d file:
ACQUIRE ../btree/bt_cursor.c 59;" d file:
ACQUIRE_COUPLE ../btree/bt_cursor.c 72;" d file:
ACQUIRE_COUPLE ../btree/bt_cursor.c 73;" d file:
ACQUIRE_CUR ../btree/bt_cursor.c 88;" d file:
ACQUIRE_CUR ../btree/bt_cursor.c 89;" d file:
ACQUIRE_CUR_COUPLE ../btree/bt_cursor.c 103;" d file:
ACQUIRE_CUR_COUPLE ../btree/bt_cursor.c 104;" d file:
ACQUIRE_WRITE_LOCK ../btree/bt_cursor.c 119;" d file:
ACQUIRE_WRITE_LOCK ../btree/bt_cursor.c 120;" d file:
ACTIVATE_CTP ../dbinc/db_server_int.h 138;" d
AES_CIPHER ../dbinc/crypto.h /^} AES_CIPHER;$/;" t
ANYSITE ../dbinc/rep.h 48;" d
BACKUP_PREFIX ../db/db.c 951;" d file:
BACKUP_PREFIX ../db/db.c 952;" d file:
BADARG ../clib/getopt.c 60;" d file:
BADARG ../clib/getopt.c 61;" d file:
BADCH ../clib/getopt.c 58;" d file:
BADCH ../clib/getopt.c 59;" d file:
BAD_KILLID ../lock/lock_deadlock.c 42;" d file:
BFMSG ../db185/db185.c 179;" d file:
BH ../dbinc/mp.h /^struct __bh; typedef struct __bh BH;$/;" t
BH_CALLPGIN ../dbinc/mp.h 268;" d
BH_DIRTY ../dbinc/mp.h 269;" d
BH_DIRTY_CREATE ../dbinc/mp.h 270;" d
BH_DISCARD ../dbinc/mp.h 271;" d