The spatial or graphic element, if present, that separates text units.
The value space indicates that the separator is a space or a space character; continuous indicates the absence of a separator (scriptio continua).
In cases where the separator is a symbol, it is possible to enter an approximation of it (e.g. a Unicode character that resembles it as closely as possible) and, optionally, its taxonomic classification.
Any valid metadata key indicating the unit separator, followed by an equal sign = and any Unicode text, including spaces, representing the spatial/graphic unit approximation. Optionally, preceded by a colon :, a taxonomic value can be specified from among those supported or a custom one.