Bug#995280: gnome-builder cannot open or create projects

[Stephan Verbücheln]

Package: gnome-builder
Version: 41.1-1

When I try to open or create a project, gnome-builder gets stuck. It
prints the following warning, which may be related:

$ gnome-builder 
05:18:55.3027                  ide-subproces-supervisor[ 7160]: 
WARNING: Failed to execute child process “/usr/libexec/gnome-builder-
flatpak” (No such file or directory)

The corresponding binary does not exist in this path or anywhere else
in /usr.

I am using Debian Sid with all recent package versions. I did not
experience this problem with gnome-builder 3.40.x.