Guilers,

What the subject says :-)  Omitting the final dot is optional (and 
common), not mandatory.

  scheme@(guile-user)> (string->uri-reference "http://x.org")
  $1 = #<<uri> … host: "x.org" …>

  scheme@(guile-user)> (string->uri-reference "http://x.org.")
  $2 = #f ; wrong!

This actually breaks redirects in the wild:

Starting download […]
From 
https://pyropus.ca/software/getmail/old-versions/getmail-5.16.tar.gz...
Bad uri-reference header component:
https://pyropus.ca./software/getmail/old-versions/getmail-5.16.tar.gz

Kind regards,

T G-R