Get Links that start with "vivaldi-stable_6" and end in "_amd64.deb" according the last example in MDN
$ baseurl='https://repo.vivaldi.com/stable/deb/pool/main/'
$ curl -s "$baseurl" |pup 'a[href^=vivaldi-stable_6][href$=_amd64.deb] attr{href}'
vivaldi-stable_6.1.3035.111-1_amd64.deb
vivaldi-stable_6.1.3035.111-1_arm64.deb
vivaldi-stable_6.1.3035.111-1_armhf.deb
Thank you for your attention.
Greetings, mszet