docker-compose.override.yml file contains images that are not available public

Describe the bug
docker-compose.override.yml example contains:

• sitecore-horizon-integration-${TOPOLOGY}-cm:${VERSION}
• sitecore-horizon-integration-${TOPOLOGY}-mssql:${VERSION}

As there is no code that can build these images in this repository or any description, where to get these images, I expect that they should be available in the official Sitecore images repository on scr.sitecore.com:
https://raw.githubusercontent.com/Sitecore/docker-images/master/tags/sitecore-tags.md

But these images are absent there.

To Reproduce
Steps to reproduce the behavior:

1. Edit your docker-compose.override.yml using examples provided in this repo
2. Run docker-compose up -d
3. See error scr.sitecore.com/sxp/sitecore-horizon-integration-xm1-mssql:10.1.0-ltsc2019 not found

Expected behavior
docker-compose should be able to download images and start containers based on that images.

• OS: Windows 10 1909

Start with docker-compose.override.yml and run docker-compose up -d using the example configuration to reproduce the missing-image error. Check the referenced Horizon integration tags against the official Sitecore image list; done means the example can pull its declared images and start the containers, or clearly identifies the required image source.