fonttools/Tests/feaLib/data/spec9b.fea

@BASE = [f i];
@LIGATURES = [c_s c_t f_i f_f_i s_t];
@MARKS = [acute grave];
@COMPONENT = [noon.final noon.initial];

table GDEF {
    GlyphClassDef @BASE, @LIGATURES, @MARKS, @COMPONENT;
    Attach noon.final 5;
    Attach noon.initial 4;
    LigatureCaretByPos f_i 400 380;
    LigatureCaretByPos [c_t s_t] 500;
    LigatureCaretByIndex f_f_i 23 46;
} GDEF;