https://bugzilla.wikimedia.org/show_bug.cgi?id=72209
--- Comment #6 from John Mark Vandenberg jayvdb@gmail.com --- The API documentation explains it
eunamespace - The page namespace(s) to enumerate. NOTE: Due to $wgMiserMode, using this may result in fewer than "eulimit" results returned before continuing; in extreme cases, zero results may be returned Values (separate with '|'): 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, .. Maximum number of values 50 (500 for bots)