The project is based on multiple open-sourced projects (listed below) all using permissive licenses.
A license for a whole project is MIT.
but if you use some part of the code please check each source file's header for the licensing info.
Font
Apache2, 2014-2016, Samuel Carlsson, Big thanks for https://github.com/vidstige/NRasterizer
MIT, 2015, Michael Popoloski, https://github.com/MikePopoloski/SharpFont
The FreeType Project LICENSE (3-clauses BSD style),2003-2016, David Turner, Robert Wilhelm, and Werner Lemberg and others, https://www.freetype.org/
Apache2, 2018, Apache/PDFBox Authors, https://github.com/apache/pdfbox
Apache2, 2020, Adobe Font Development Kit for OpenType (AFDKO), https://github.com/adobe-type-tools/afdko
Text Processing
Unicode (BSD style), 2020, UNICODE, INC, https://www.unicode.org/license.html
Apache2, 2014 , Muhammad Tayyab Akram, https://sheenbidi.codeplex.com/ , https://github.com/Tehreer
Geometry
BSD, 2002-2005, Maxim Shemanarev, Anti-Grain Geometry - Version 2.4 http://www.antigrain.com
BSD, 2007-2014, Lars Brubaker, agg-sharp, https://github.com/MatterHackers/agg-sharp
MIT, 2016, Viktor Chlumsky, https://github.com/Chlumsky/msdfgen
BSD, 2009-2010, Poly2Tri Contributors, https://github.com/PaintLab/poly2tri-cs
Apache2, 2016-2017, WinterDev, https://github.com/PaintLab/PixelFarm
Platforms
MIT, 2015-2015, Xamarin, Inc., https://github.com/mono/SkiaSharp
MIT, 2006-2009, Stefanos Apostolopoulos and other Open Tool Kit Contributors, https://github.com/opentk/opentk
MIT, 2013, Antonie Blom, https://github.com/andykorth/Pencil.Gaming
MIT, 2004, 2007, Novell Inc., for System.Drawing
Unpack, Zlib,Brotli
MIT, 2018, SharpZipLib, https://github.com/icsharpcode/SharpZipLib
MIT, 2009, 2010, 2013-2016 by the Brotli Authors., https://github.com/google/brotli
MIT, 2017, brezza92 (C# port from original code, by hand), https://github.com/brezza92/brotli
MIT, 2019, master131, https://github.com/master131/BrotliSharpLib
Demo
MIT, 2017, Zou Wei, https://github.com/zwcloud, see more Zou Wei's GUI works at here and here
MIT, 2020, brezza92 (https://github.com/brezza92), MathML layout engine