python3-slixmpp-lib 1.8.3-1build1 (s390x binary) in ubuntu lunar

 Slixmpp is a (friendly) fork of SleekXMPP, which goal is to “improve” the
 core of the library by entirely removing all threads from the library and
 using an event-based approach instead.
 .
 This is an optional package that installs a binary extension module to
 improve performance on critical modules.