libxmuu-dev 2:1.1.3-3 (riscv64 binary) in ubuntu mantic

 libXmuu provides a set of miscellaneous utility convenience functions for X
 libraries to use. It is a lighter version of libXmu that does not depend
 on libXt or libXext; for more information on libXmu, see libxmu6.
 .
 This package contains the development headers for the library found in
 libxmuu1. Non-developers likely have little use for this package.
 .
 More information about X.Org can be found at:
 <URL:http://www.X.org>
 .
 This module can be found at
 git://anongit.freedesktop.org/git/xorg/lib/libXmu