% ----

Output from mtxrun --script fonts --list

fontinregular                       Fontin Regular                    Fontin-SmallCaps.otf
fontinsans                          Fontin Sans Rg Bold               Fontin_Sans_BI_45b.otf
fontinsansrgbold                    Fontin Sans Rg Bold               Fontin_Sans_BI_45b.otf
fontinsansrgnormal                  Fontin Sans Rg Normal             Fontin_Sans_I_45b.otf
fontinsansrgregular                 Fontin Sans Rg Regular            Fontin_Sans_R_45b.otf
fontinsansscregular                 Fontin Sans Sc Regular            Fontin_Sans_SC_45b.otf

...

museo                               Museo 700 Bold                    Museo700-Regular.otf
museo700bold                        Museo 700 Bold                    Museo700-Regular.otf
museoregular                        Museo 700 Bold                    Museo700-Regular.otf

% ------
From the type-exljbris.tex file

\starttypescript [serif] [fontin]
    \setups[font:fallback:serif]
    \definefontsynonym [Serif]           [Fontin-Regular]
    \definefontsynonym [SerifItalic]     [Fontin-Italic]
    \definefontsynonym [SerifBold]       [Fontin-Bold]
    \definefontsynonym [SerifBoldItalic] [SerifBold]
    \definefontsynonym [SerifCaps]       [Fontin-Caps]
\stoptypescript

\starttypescript [sans] [fontin]
    \setups[font:fallback:sans]
    \definefontsynonym [Sans]           [FontinSans-Regular]
    \definefontsynonym [SansItalic]     [FontinSans-Italic]
    \definefontsynonym [SansBold]       [FontinSans-Bold]
    \definefontsynonym [SansBoldItalic] [FontinSans-BoldItalic]
    \definefontsynonym [SansCaps]       [FontinSans-Caps]
\stoptypescript

\starttypescript [fontin]
    \definetypeface [fontin] [rm] [serif] [fontin]   [default]
    \definetypeface [fontin] [ss] [sans]  [fontin]   [default]
    \definetypeface [fontin] [tt] [mono]  [modern]   [default] [rscale=1.1]
    \definetypeface [fontin] [mm] [math]  [palatino] [default]
\stoptypescript

And from the t-irex.tex file:

\definefont [interludefont]   [name:museo700 at 28pt]
\definefont [chapterfont]     [name:museo700 at 32pt]