Which Darwin Core term each column of a species occurrence or checklist file maps to, by the header rules our file-to-archive converter runs before it checks values: for each column the term, the rule that decided it (exact name or alias, a word of the name, a packed coordinate pair, a grid reference), the alias that matched and where it came from, or a coded refused block saying why it stays unmapped (no term or alias matches, several columns tie for one term, another column holds the term, blank in the sample). Also names the terms GBIF requires of an occurrence or a checklist dataset that no column carries. Values are not checked here: each mapped column names the value check it must still pass.