Hi,
... as promised, here is essentially what Uwe mentioned: Under my
setup, it is acceptable that 'loon' (package 'bar') appears in
Suggests and that the DESCRIPTION text mentions how to install 'loon'
(from github; provide a link in the text with '<>') if the user wants
to do the plotting with 'loon'. That makes a lot of sense in my case.
Thanks everyone for helping on this.
Many cheers,
Marius