The xBlog controls with the showUid URL parameter and Fluid templates. Usually you select the value for the showUid in the flexform.
But if the table has this TCA property configures, the showUid for this table is determined. A user don't need to decide, what is a proper showUid.
If this property isn't enabled, this table will not be displayed in the flexforms of the xBlog plugins.
Value (string): a defined showUid from the list below.
$GLOBALS['TCA'][tx_org_news]['ctrl']['extensions']['xblog']['showUid'] = 'newsUid';
boardUid, calUid, downloadUid, eventUid, feuserUid, itemUid, jobUid, locationUid, newsUid, organiserUid, serviceUid, showUid and staffUid