Page-scan holders now return the artifact URL instead of [None].
lastversion <page-scan repo> --assets crashed with TypeError: sequence item 0: expected str instance, NoneType found. Holders that scrape a links page have no RELEASE_URL_FORMAT, so release_download_url() returned None and get_assets() appended it verbatim. A falsy download URL is now simply not an asset.
The feed holder can do better: the hyperlink it matched on is the artifact location, so it is kept (absolute) and returned as the download URL.
A releases page typically links both the tarball and its release notes for the same version (varnish-6.0.18.tgz next to rel6.0.18.html). Both sanitize to the same version, so ties now break towards the archive rather than document order.
Pre-existing since the page link-scan landed in 3.6.13.