- atom-ns-prefixesparameter
An alist of XML namespace prefixes used when reading or writing feeds. Most known namespaces relevant to Atom are included, so it is normally not necessary to touch this unless you come across an unusual namespace.
A symptom of a missing namespace is that on read, some feed elements are qualified with a full URI instead of a prefix abbreviation, and on write that some are qualified with namespace 'prfx1:' or the like.