malt vinegar is often a side product from beer brewing – which explains prevalence in UK, US, Canada – but from a quick glance, looks like it’s missing from German or Czech cuisine (preference seems to be fruit, herb, and spirit vinegars)

depends on what you’re using it for, but I think closest substitute would be apple cider vinegar – some apple notes in the aroma but often shows up in UK, US, and Canadian cuisine as a “fancy” alternative to malt vinegar