I use MW 1.25.3 with Extension:SemanticDrilldown master (17. Jan. 2016) and on Special:Browse a SQL error is issued (see forelast line):
SELECT DISTINCT
ids.smw_title AS title,
ids.smw_title AS value,
ids.smw_title AS t,
ids.smw_namespace AS namespace,
ids.smw_namespace AS ns,
ids.smw_id AS id,
ids.smw_iw AS iw,
ids.smw_sortkey AS sortkey
FROM `smw_object_ids` ids
JOIN `smw_fpt_inst` insts ON ids.smw_id = insts.s_id AND ids.smw_namespace != 14
JOIN a0 ON ids.smw_id = a0.s_id
WHERE insts.o_id IN (
SELECT smw_id
FROM `smw_object_ids` cat_ids
WHERE smw_namespace = 14
AND (smw_title = 'Gedicht' OR smw_title = 'Gedichttext' OR smw_title = 'Tischspruch')
)
AND a0.p_id = (
SELECT MAX(smw_id)
FROM `smw_object_ids`
WHERE smw_title = '' AND smw_namespace = 102
) AND (a0. = 'Gedicht')
ORDER BY sortkey LIMIT 251
… I tries to execute `a0. = 'Gedicht'` where a0 seems like an alias of some kind but it is never defined. The debug tells it is executed by `SDBrowseDataPage::reallyDoQuery`