Reading sample files from the ofxstatement-bubbas project (cloned at run time, nothing copied) through ai-bookkeeper's reader turned up two faults. DKB's credit-card export names its description column Umsatzbeschreibung, and flatex's account export calls it Buchungsinformationen. Neither was a known header, so every row imported with an empty description and the categorizer had nothing to work with. Both are aliases now, with two tests on made-up rows.
Still open: a headerless 7-column Amazon-card CSV from LBB reads zero rows.