fluid 1.3.4-6 (i386 binary) in ubuntu bionic

 This package provides Fluid, an interactive GUI designer for FLTK,
 allowing graphical development of FLTK-based user
 interfaces. It natively works with (textual) .fl files, but also
 includes rough support for reading .fd files produced by fdesign (in
 libforms-bin).
 .
 The Fast Light Toolkit (FLTK) is a cross-platform graphical user interface
 toolkit originally based on libForms.