https://bugs.winehq.org/show_bug.cgi?id=42238
--- Comment #4 from Andrew Udvare audvare@gmail.com --- The developers forced MS Sans Serif. They use SystemParametersInfo() to get the metrics on how to draw the font. They use CreateFontIndirect() to get the GDI object structure for more metric data. Weird since it is just plain old MS Sans Serif at 8 point.
On a side note, the app is written in Delphi and appears to use the VCL for rendering including text. This seems to mean no ClearType without extra work: https://stackoverflow.com/questions/921249/font-smoothing-in-delphi . So the developers are not doing it.
Hacky workaround: unpack binary, hex edit:
4d532053616e732053600 ("MS Sans Serif\0")
to
5365676f6520554900000 ("Segoe UI\0\0\0\0\0\0")
Still confusing though because in this case, it must be that fontconfig steps in before Wine and smooths out Segoe UI but refuses to present a smooth version of MS Sans Serif (no hints in the font?).