Standard: http://www.w3.org/TR/xslt#element-decimal-format
decimal-format
Attributes: name, decimal-separator, grouping-separator, percent, per-mille, zero-digit, digit, pattern-separator, infinity, NaN, minus-sign
Standard excerpt:
The xsl:decimal-format element declares a decimal-format, which controls the interpretation of a format pattern used by the
format-number function. If there is a name attribute, then the element declares a named decimal-format; otherwise, it declares
the default decimal-format. The value of the name attribute is a QName. It is an error to declare either the default decimal-format
or a decimal-format with a given name more than once (even with different import precedence), unless it is declared every
time with the same value for all attributes (taking into account any default values).