Compile with pdflatex or xelatex?

The fonts used in a latex document affects the compilation engine.

void IsFontCompatibleToXeLatex(string fontFamilyName, string latexFileContent) {
    if (latexFileContent.Contains("\usepackage{fontspec}"))
    {
        Console.WriteLine($"{fontFamilyName} will be loaded from font files of your operating system.");
        return;
    }

    string package = FindPackage(fontFamilyName);
    var files = LoadPackage(package);

    bool hasTU = files.Contains($"TU{fontFamilyName}.fd");
    bool hasLegacy = files.Contains($"T1{fontFamilyName}.fd") || files.Contains($"OT1{fontFamilyName}.fd");

    if (!hasTU && hasLegacy)
        Console.WriteLine($"{package} provides {fontFamilyName} only in 8-bit encoding; use with pdfLaTeX.");
    else
        Console.WriteLine($"{fontFamilyName} can be used with XeLaTeX.");
}

TODO: kpsewhich

See also https://tex.stackexchange.com/questions/373617/latex-fonts-for-dummies