4025 Fire Boat

[Stefan Frenz]

That's right, but the qualifier only starts with 2 if there are several models.
Look here: https://www.ldraw.org/article/593.html#base_file_naming

Thank you for insisting - I read the article some weeks ago when I started building models for OMR. I clearly did it wrong, perhaps because of my (also still very low) experience with BrickLink and Rebrickable, where I found most of my sets listed with "-1". Future filenames won't have "-1".