Didier Kryn:
...
>     Karl, since you seem to have a pretty good understanding of this
> matter, may be a little tutorial would be welcome.

(I'm forced to that since the rug is swept from under my feets...)

Yes why not. I can write part of it but I need to know which questions
it should answer, and it should be made available somewhere.

Since devuan is about init freedom, why not set up a documentation place
at https://www.devuan.org/ describing booting and various choises in
that process complete with a comparision of some inits ?

Regards,
/Karl Hammar