Comment 1 for bug 1855519

Thanks for taking your time to report this issue and help making Ubuntu better.

This was resolved in the corresponding Debian bug report, and the additional dependency is included in the displaycal version in the upcoming Ubuntu Focal.

If you need a fix previous versions of Ubuntu (19.10 or older), please perform as much as possible of the SRU Procedure (see https://wiki.ubuntu.com/StableReleaseUpdates#Procedure) to bring the need to a developer's attention. (I can possibly help provide a patch here)
Also, when reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. This adds relevant debug information such as package version and affected Ubuntu release. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.