Sorry, you can ignore my question:
Uwe Liges clarified to me that the other error in my CRAN submission check
is definitely a problem I need to address.
And from this post by Hadley on Twitter I conclude that the URL warning can
be ignored: https://twitter.com/hadleywickham/status/13581706073142353
I suspect that this is an issue with the CRAN Windows machine, not
with your package.
If you want to work around it in the incoming checks, you can remove
the URL. Maybe it is enough to remove the `https://` from the
beginning, but I am not sure.
Gabor
On Wed, Feb 17, 2021 at 4:33 PM Vincent van