Duplicates in pango-list
Doesn't cause any visible problems, but pango_font_face_get_face_name() documents:
Gets a name representing the style of this face among the different faces in the PangoFontFamily for the face. This name is unique among all faces in the family and is suitable for displaying to users.
And test_enumerate in test-font fails for these fonts.
Duplicates on my system:
pango-list | uniq -d
Regular: Asana Math
Thin: Cantarell Thin
Light: Cantarell Light
Extra Bold: Cantarell Ultra-Bold
Regular: TeX Gyre Pagella Math
Medium: Neo Euler Medium
Regular: Goha-Tibeb Zemen Medium
ExtraLight: Source Code Pro Ultra-Light
Light: Source Code Pro Light
Regular: Source Code Pro
Medium: Source Code Pro Medium
Semibold: Source Code Pro Semi-Bold
Bold: Source Code Pro Bold
Black: Source Code Pro Heavy
Regular: Latin Modern Math
Regular: TeX Gyre Termes Math