Crystallography Online: the website of the International Union of Crystallography

I added my own prefix to the prefix registry for general-purpose local
data types. Perhaps it would be better to generalize the idea similar to
mail/HTTP and other internet headers which reserve the "X-" prefix to
mean a non-standard name. This could be reserved for local developmental
work, or temporary additions not defined in the current dictionary.

Is this an acceptable idea? Is anyone already using a data name starting
with "X-"? (I wouldn't be too surprised if there is a "X-Ray..." name.

Joe