tcl-xpa binary package in Ubuntu Xenial arm64

 The XPA messaging system provides seamless communication between many kinds
 of Unix programs, including X programs and Tcl/Tk programs. It also provides
 an easy way for users to communicate with these XPA-enabled programs by
 executing XPA client commands in the shell or by utilizing such commands in
 scripts. Because XPA works both at the programming level and the shell level,
 it is a powerful tool for unifying any analysis environment: users and
 programmers have great flexibility in choosing the best level or levels at
 which to access XPA services, and client access can be extended or modified
 easily at any time.
 .
 This package contains the Tcl interface.

Source package