According to section 3 Getting Started on p. 4 of the
unicode-math package documentation for the user version 2020/01/31 0.8q (which is the current version), here's an example using the filename syntax to load the TeX Gyre Pagella Math font:
What if a math font encompasses several
.otf files? For instance, the STIX Two font encompasses 5
How can I configure the document to use this font in math mode? (And only in math mode.)
Or should I be concerned only with STIX2Math.otf if I want to use the STIX font only in math mode, because the other files are intended for use in text mode? But maybe the STIX2Text-....otf files are meant for typesetting variables in math mode, in which case they are indispensable.
P.S. I use LuaLaTeX as my LaTeX compiler.