Hello Humdinger & Others;
When synchronizing the localization, it may be a nice option to view the
project in the JetBrain Intelli-J  tool. If you double click on one of the
localization files and then choose the "Resource Bundle" tab at the bottom of
the view, you will see  the keys with each language adjacent. It is then
possible to compare and work with each localization concurrently. I am looking
at the pay-for version, but this is probably possible in the community edition
too I guess.
To open a project, choose the HDS project file "pom.xml" and the rest should
hopefully be straight forward.