When parameters for the action are incorrectly entered, the format argument is ignored and the result is format=xmlfm. This can potentially break many clients.
Example: http://en.wikipedia.org/w/api.php?format=xml&action=
should produce xml, not xmlfm format.
Version: unspecified
Severity: minor
URL: http://en.wikipedia.org/w/api.php?format=xml&action=