If you want to test the current state of Xfce 4.16, you can look at xfce-test, a Docker image by Florian Schueller which allow you to test git master and to run Behave (behaviour-driven development).

Xfce Test is a Docker/Xephyr environment for testing the latest builds of Xfce.

• Clone the xfce-test repository git clone https://github.com/schuellerf/xfce-test
• Change to the repository directory and install the necessary components ( ./xfce-test install )
  • On Xubuntu 20.04, this will install the following packages and their dependencies, if they aren’t already present - xserver-xephyr, docker.io, xvfb, jq, and curl - which will download ~71Mb and require 351Mb of space
• Download the docker container ( sudo ./xfce-test pull )
  • This will download the Docker container part of schuellerf/xfce-test which is ~1.6Gb and require ~4.4Gb of space (as of May 2020).

If xfce-test is run without any options, the xfce-test script will present output that consists of two parts. First, the various option flags that can be used to modify the starting of the script. And, secondly, a numbered menu that appears, as follows:

At this point the user will be prompted for an option to select.

To simply run the container from the command line, use the command: ( ./xfce-test start )

• Remove the docker container
  • Find the schuellerf/xfce-test container’s image ID ( docker images -a )
  • Remove the container ( docker rmi [image’s ID] )
• Remove the installed packages
  • Remove main packages ( sudo apt remove xserver-xephyr docker.io xvfb jq curl )
    • Note: you may not want to remove some of these packages if they weren't installed during the xfce-test installation
  • Remove dependencies ( sudo apt autoremove )