The msg_resource_links table was a table used for tracking which messages are contained in which resources.
Message blobs [1] were cached in the msg_resource table and automatically invalidated when one of their constituent messages or the resource itself were changed.
See Manual:MessageBlobStore.php.
Fields
mrl_resource
ResourceLoader module name.
mrl_message
Message key.
Schema summary
MediaWiki versions:
1.17 – 1.26
DESCRIBEmsg_resource_links;
+--------------+----------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+----------------+------+-----+---------+-------+
| mrl_resource | varbinary(255) | NO | PRI | NULL | |
| mrl_message | varbinary(255) | NO | PRI | NULL | |
+--------------+----------------+------+-----+---------+-------+
References
↑blobs for example are JSON objects containing the interface messages for a certain resource in a certain language