stack-trace-on-error vs. debug-on-error.

[Lute Kamstra]

Does anyone know the difference between stack-trace-on-error and
debug-on-error?

,----[ C-h v stack-trace-on-error RET ]
| stack-trace-on-error's value is nil
| 
| *Non-nil means errors display a backtrace buffer.
| More precisely, this happens for any error that is handled
| by the editor command loop.
| If the value is a list, an error only means to display a backtrace
| if one of its condition symbols appears in the list.
| 
| You can customize this variable.
| 
| Defined in `C source code'.
`----

,----[ C-h v debug-on-error RET ]
| debug-on-error's value is nil
| 
| *Non-nil means enter debugger if an error is signaled.
| Does not apply to errors handled by `condition-case' or those
| matched by `debug-ignored-errors'.
| If the value is a list, an error only means to enter the debugger
| if one of its condition symbols appears in the list.
| When you evaluate an expression interactively, this variable
| is temporarily non-nil if `eval-expression-debug-on-error' is non-nil.
| See also variable `debug-on-quit'.
| 
| You can customize this variable.
| 
| Defined in `C source code'.
`----

On first inspection they seem to do exactly the same.
stack-trace-on-error is not documented in Emacs manual or the Lisp
manual.  Would it be safe to make it an alias of debug-on-error and
mark it as obsolete?

Lute.