Re: Undo mode

[Gregory Heytings]

> > We are not going to enable undelete-frame-mode by default.
>
> I don't think I understand the benefit of hiding this behind a mode. It 
> seems to me that the major difference it will make is that the 
> `undelete-frame' command won't work by default.

See bug#51883.  The conclusion was that undeleting frames is not a feature 
that all users need, and that enabling it by default uses some memory.