disable-point-adjustment is a variable defined in `C source code'.
Its value is

If non-nil, suppress point adjustment after executing a command.

After a command is executed, if point is moved into a region that has
special properties (e.g. composition, display), we adjust point to
the boundary of the region. But, when a command sets this variable to
non-nil, we suppress the point adjustment.

This variable is set to nil before reading a command, and is checked
just after executing the command.