edit Edit M-file.
edit FUN opens the file FUN.M in a text editor.  FUN must be the
name of an m-file or a MATLABPATH relative partial pathname (see
PARTIALPATH).

edit FILE.EXT opens the specified text file.

edit FUN1 IN FUN2 opens function FUN1 in the context of m-file
FUN2.

edit FUN(A,B,C) opens file FUN.M that matches the
given input arguments.  For example, edit feval(g), when
g=inline(‘sin(x)’), opens inline/feval.m.

EDIT, by itself, opens up a new editor window.
Overloaded methods
help axischild/edit.m