Yes. I just looked at the api data to see what travellermap actually sent.

Just changing the number on the top doesn't work unfortunately, as the code that created the import explicitly sets a color for every border, and it uses 15 if it gets (what it considers) an invalid color from travellermap.

What you need to change are the color values:

#COLORS
#======
color names = red:2|blue:9|olivedrab:12|orange:8|yellow:4|purple:7|green:13|lightgreen:1|lightblue:9|pink:187|brown:11|cyan:5|hotpink:6|lime:118|darkred:165|darkkhaki:130|gray:14|slategray:67|darkslategray:66|white:15|indigo:58

This section is also what makes Darian and Sword Worlds the same color. Travellermap sends color blue for one of them and lightblue for the other, and if you look at the config, those are both set to be color 9.

You can also get it to use those html colors just by inserting them into the list, like I did here, this should cause the white sections on Spineward Marches to come out as yellow:

color names = red:2|#e32736:135|blue:9|olivedrab:12|orange:8|yellow:4|purple:7|green:13|lightgreen:1|lightblue:9|pink:187|brown:11|cyan:5|hotpink:6|lime:118|darkred:165|darkkhaki:130|gray:14|slategray:67|darkslategray:66|white:15|indigo:58

The way we handle these colors was written before travellermap started putting those html color codes in there, so I am afraid this is a manual process for now to identify and insert appropriate replacement, the importer would need an update to be able to parse those automatically. Personally, I would probably just do some quick manual color changes on those entities after loading the map. While having everything correct out of the gate is obviously preferable, the main work is in drawing the sectors after all.

Also note one thing about the import dialog. It caches the setting sin memory when you load the file, so if you make tweaks to the config file with CC3+ open and want to test the new settings, you need to click the change export settings button and browse for the file again, even if the dialog indicates it is already the right file.

This entity is the color palette the drawing is using. A custom color palette is one of the hidden entities that are possible in a map. You could detach it from the drawing presets dialog, but this will have your map revert to using the default palette.

@ is the standard CC3+ reference to the CC3+ data directory, the default location unless you changed it during installation is c:\ProgramData\ProFantasy\CC3Plus

System is a folder within the data directory.

You'll find a lot of it in the tome somewhere, but there is no dedicated section just describing the special sheets, it's more a thing you pick up a bit from here and a bit from there.

For the SCREEN sheet, it's not that special, really, but because the canvas in CC3+ is unlimited in size, if you put a symbol at the "edge" of the the map, it won't be clipped, it will simply extend off it. The SCREEN sheet typically holds a white polygon that simply covers up all those bits sticking out.

For the MAP BORDER, the map border sheet just holds the graphical decorative map border. It is usually placed last in the list to put a nice frame on top of things. The "technical" map border, which define the size of the maps, and that drawing tools use as the edge to know where to stop drawing, is simply 4 lines on the MAP BORDER layer, they can be on any sheet, but usually the live on BACKGROUND.