bug#30204: 27.0.50; Changing major mode resets non-default invisibility spec

[Kévin Le Gouguec]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Richard Stallman <rms@gnu.org> writes:
>
>> M-x poverty-mode and M-x vow-of-poverty-mode
>> can complete from only 2 or 3 characters.
>> Likewise M-x no-properties-mode.
>
> It also removed overlays and local variables, so it's not all about text
> properties...

Maybe the name should emphasize the _lack_ of any features whatsoever,
rather than the _removal_ of features?  E.g. void-mode, null-mode,
nil-mode, empty-mode, bare-mode, plain-mode?