Plasma 5: screen locker font color

[solitone]

I am on Plasma 5, and I've been using the pre-installed Breeze Dark theme for 
some time, but now I've just installed the Naked desktop theme [1], through 
the Get new Theme functionality in System Settings.

I like it, but there is one thing that annoys me. The font color in the screen 
locker used to be white in Breeze Dark, as well as any other standard theme, 
but in Naked it is black. Since I use a pretty dark background image in the 
screen locker, readability is low. I'd rather have a white font color, like 
previously.

I've found the directory where the Naked theme is installed:
~/.local/share/plasma/desktoptheme/Glaze

The Glaze name is confusing, but it's the correct directory:

solitone at alan:~/.local/share/plasma/desktoptheme/Glaze$ cat metadata.desktop 
[Desktop Entry]
Name=Naked
[...]

I can't find anything related to the screen locker in that directory, though. 
There is a file called colors, but it seems there is nothing referring to the 
screen locker.

So, have you got any idea as to where I can customise the appearance of the 
screen locker? What is that changes the font color to black, in a desktop 
theme? 

[1] https://store.kde.org/p/998856