Ladies and Gentlemen, I screwed up.
I used (I think) Resource Hacker to add a certain color or color name to the palette of LibreOffice, at least something of that sort. I definitely didn’t get it done with LibreOffice itself, that’s why I resorted to the aforementioned “hack”. But now, whenever I choose a color to be used as the text color, it has no effect. However, other colors work, such as text background color. The problem only persists within my current user profile, which I can also see from the fact that it persisted through LibreOffice 5.0 being installed. However, I can’t just delete my current profile, as I have precious customizations in there, such as the button arrangements and icon replacements. So, the question would be, how to either restore the text color module by copying something from the standard profile, or, how to secure the “button arrangements and icon replacements” part of my current profile and import it into a fresh standard profile.