erlang-yapp binary package in Ubuntu Focal s390x

 Yaws-yapp (Yaws application handler) is a helper application.
 It takes care of adding, and removing, the applications into a running
 server. When anyone access the server with an URL that matches the path
 for an added application, the docroot will be temporarily switched
 to where the web pages for that application are located.
 .
 This package includes the Yapp Erlang module which can be used in Yaws
 embedded mode without separate server config.

Source package