compose-chars-after-function is a variable defined in `C source code'.
Its value is

  • This variable may be risky if used as a file-local variable.

Function to adjust composition of buffer text.

This function is called with three arguments: FROM, TO, and OBJECT.
FROM and TO specify the range of text whose composition should be
adjusted. OBJECT, if non-nil, is a string that contains the text.

This function is called after a text with `composition' property is
inserted or deleted to keep `composition' property of buffer text

The default value is the function `compose-chars-after'.