= Wikipedia dumps
Per-table dumps created with <mysqldump> and listed at: https://dumps.wikimedia.org/[]. Most notably, for the English Wikipedia: https://dumps.wikimedia.org/enwiki/latest/
A few of the files are not actual tables but derived data, notably http://dumps.wikimedia.org/enwiki/latest/enwiki-latest-all-titles-in-ns0.gz from <Download titles of all Wikipedia articles>
The tables are "documented" under: https://www.mediawiki.org/wiki/Manual:Database_layout[], e.g. the central "page" table: https://www.mediawiki.org/wiki/Manual:Page_table[]. But in many cases it is impossible to deduce what fields are from those docs.