SUMMARY


STEPS TO REPRODUCE
1. sudo apt-get install qt5ct 

OBSERVED RESULT
murych@murych-hp:~$ sudo apt-get install qt5ct

Starting pkgProblemResolver with broken count: 1
Starting 2 pkgProblemResolver with broken count: 1
Investigating (0) qt5ct:amd64 < none -> 0.39-1build3 @un puN Ib >
Broken qt5ct:amd64 Depends on qtbase-abi-5-12-8:amd64 < none @un H >
  Considering libqt5core5a:amd64 3687 as a solution to qt5ct:amd64 9999
Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 qt5ct : Depends: qtbase-abi-5-12-8
E: Unable to correct problems, you have held broken packages.


EXPECTED RESULT
Normal install

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
Latest Neon User Edition64-bit rebased on Ubuntu 20.04 LTS 

Operating System: KDE neon 5.20
KDE Plasma Version: 5.20.4
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.2
Kernel Version: 5.4.0-56-generic
OS Type: 64-bit
Processors: 4 × Intel® Core™ i3-2370M CPU @ 2.40GHz
Memory: 7.7 ГиБ of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 3000


ADDITIONAL INFORMATION
Kubuntu 20.04 works like expected