Table.phpbb forums track
From phpBB Development Wiki
This table keeps record for visited forums in order to mark them as read or unread. We use the mark_time timestamp in conjunction with last post of forum x's timestamp to know when all topics in forum x were last marked read.
In order to accurately tell whether a given topic is read, one has to also check phpbb_topics_track.
|user_id||mediumint(8) unsigned||primary key||0|
|forum_id||mediumint(8) unsigned||primary key||0|