Parameter "usefilenames"

kalibrierschein/kalibrierschein.cls

@@ -7,7 +7,7 @@
 \newcommand*\ks@langs{ngerman,main=english}
 \NeedsTeXFormat{LaTeX2e}[1999/12/01]
 \ProvidesClass{kalibrierschein}
-  [2019/03/13 v0.4b Dokumentenklasse (RN/PTB)]
+  [2019/03/21 v0.4c Dokumentenklasse (RN/PTB)]
 \DeclareOption{BS}{\def\ks@location{Braunschweig}}
 \DeclareOption{BLN}{\def\ks@location{Berlin}}
 \DeclareOption{KK}{\edef\ks@kalType{\CurrentOption}}
@@ -152,8 +152,9 @@ footskip=0bp,
   UprightFont=*-regular,
   BoldFont=*-bold,
   ItalicFont=*-italic,
-  BoldItalicFont=*-bolditalic.otf]
-\RequirePackage{firamath-otf}
+  BoldItalicFont=*-bolditalic.otf] 
+\def\fira@weight{Regular}% wegen bug in "firamath-otf" (2018/09/17 v. 0.01)
+\RequirePackage[usefilenames]{firamath-otf}
 \RequirePackage[italic]{mathastext}
  
 \def\prim@s{\/\prime\futurelet\@let@token\pr@m@s}