"..." would only be a problem for implementation with a pre-SRFI 46
syntax-rules expander. But these can possibly cope with "___".

Am So., 30. Aug. 2020 um 02:15 Uhr schrieb John Cowan <xxxxxx@ccil.org>:
>
> We already have ..., so let's just leave it at that.
>
> On Sat, Aug 29, 2020 at 7:46 PM Felix Thibault <xxxxxx@gmail.com> wrote:
>>
>> Is there a particular substitute, like ^^^, :::, ???, or something else that appeals to anyone?