I believe there is a mistake in the German translation of CCleaner.
In the Applications tab, for both Firefox and Google Chrome, in each case the last checkbox is labeled "Kompakte Datenbanken" (literally: Compact databases.) However, I would assume that in the English version of CCleaner, the word "Compact" is a verb, not an adjective. "Kompakte", on the other hand, is an adjective. This changes the meaning. A user might get the idea that ticking the checkbox will mean that "compact [adjective] databases" will be deleted.
So, the German translation should be changed so that it is the verb and not the adjective. Unfortunately, there is no direct equivalent for "to compact" in the German language. Possible alternatives are "Datenbanken konsolidieren" (Consolidate databases) or "Datenbanken komprimieren" (Compress databases).
If I had a Vote it would be Datenbanken komprimieren" (Compress databases).
However I don't
The developers do read all threads (though they rarely comment) so they will take this into advisement
On second thought, "Datenbanken komprimieren" (Compress databases) is in fact better, as "consolidate" also carries the meaning of merging multiple databases into a single one, which is undesired here.