Classically, you'd do things like replace f+i with an fi glyph, or f+f+i into an ffi. Though I'm surprised that it can be used to split one glyph into multiple

Classically, you'd do things like replace f+i with an fi glyph, or f+f+i into an ffi. Though I'm surprised that it can be used to split one glyph into multiple glyphs, then transform those glyphs again.