It's complicated, that's why I asked the developer to do it.
Normally, Ren'Py script files are .rpy. When you start the game, they get compiled to .rpyc ("byte codes", not human-readable, but faster in execution). Then the game would use those compiled .rpyc (until newer .rpy appears, which would become re-compiled as new .rpyc).
Often to save space developers don't include .rpy in the game files, only .rpyc. So in order to change anything, you would need to decompile .rpyc into .rpy, and then edit those.
Also developers usually pack the game files into archives, type .rpa. So in order to change something in a game you might need to:
(1) Unpack .rpa (for instance, there are often files with names like scripts.rpa or archive.rpa). That would usually give you .rpyc (and sometimes .rpy).
(2) If there are .rpyc, but no .rpy, then you need to decompile .rpyc into human readable and editable .rpy.
There are tools for that, in particular, UnRen (you can find it in "Tools" of this forum). It can unpack .rpa and decompile .rpyc. Then you can edit .rpy or add your own scripts. (Any .rpy script inside "game" folder would be read and executed. That's how you mod those games.)
Normally Ren'Py would use your newer files instead of those originals in .rpa archives.
However, sometimes conflicts happen, as in the case of this game. It uses some optimized loading I think (I didn't really analyze it much). So simple modding of "default" characters would probably not work.
Meanwhile, there is a palliative solution: change text outlines. It would slightly improve readability of that dark text.
Put the attached file in "game" folder. You could change the outlines there to your liking. It basically changes one string:
text what id "what"
into
Code:
text what id "what" outlines [(absolute(3), "#000", 0, 0), (absolute(1), "#fff", 0, 0)]
Which means add black outline 3px wide and on top of it white outline 1px wide.
PS. See the difference:
View attachment 1141189
View attachment 1141187