Manual:Protected titles table

Contains protection of non-existent pages, the list of protected pages can be found at Special:Protectedtitles.

pt_namespace
Namespace

pt_title
Page title

pt_user
User id of user who protected the page title

pt_reason
Protection comment

pt_timestamp
Timestamp of when the protection action was taken

pt_expiry
Timestamp of when the protection expires

pt_create_perm
Protection level

Versions
mysql> describe protected_titles; ++--+--+-+-+---+ ++--+--+-+-+---+ ++--+--+-+-+---+
 * Field         | Type             | Null | Key | Default | Extra |
 * pt_namespace  | int(11)          | NO   | PRI | NULL    |       |
 * pt_title      | varbinary(255)   | NO   | PRI | NULL    |       |
 * pt_user       | int(10) unsigned | NO   |     | NULL    |       |
 * pt_reason     | tinyblob         | YES  |     | NULL    |       |
 * pt_timestamp  | binary(14)       | NO   | MUL | NULL    |       |
 * pt_expiry     | varbinary(14)    | NO   |     |         |       |
 * pt_create_perm | varbinary(60)   | NO   |     | NULL    |       |

DESCRIBE protected_titles; in version 1.18 gives the following: ++--+--+-+-+---+ ++--+--+-+-+---+ ++--+--+-+-+---+
 * Field         | Type             | Null | Key | Default | Extra |
 * pt_namespace  | int(11)          | NO   |     | 0       |       |
 * pt_title      | varbinary(255)   | NO   |     |         |       |
 * pt_user       | int(10) unsigned | NO   |     | 0       |       |
 * pt_reason     | tinyblob         | YES  |     | NULL    |       |
 * pt_timestamp  | varbinary(14)    | NO   |     |         |       |
 * pt_expiry     | varbinary(14)    | NO   |     |         |       |
 * pt_create_perm | varbinary(60)   | NO   |     |         |       |

DESCRIBE protected_titles; in version 1.12 gives the following: ++--+--+-+-+---+ ++--+--+-+-+---+ ++--+--+-+-+---+
 * Field         | Type             | Null | Key | Default | Extra |
 * pt_namespace  | int(11)          | NO   | PRI |         |       |
 * pt_title      | varchar(255)     | NO   | PRI |         |       |
 * pt_user       | int(10) unsigned | NO   |     |         |       |
 * pt_reason     | tinyblob         | YES  |     | NULL    |       |
 * pt_timestamp  | binary(14)       | NO   | MUL |         |       |
 * pt_expiry     | varbinary(14)    | NO   |     |         |       |
 * pt_create_perm | varbinary(60)   | NO   |     |         |       |