It seems like the issue discussed in [0] is back, but this time for XSL imports via xsltproc. The http link now redirects with a 301 (since when I don't know, but it worked recently):
$ curl -I http://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl HTTP/1.1 301 Moved Permanently Date: Fri, 30 Sep 2022 09:20:00 GMT Connection: keep-alive Cache-Control: max-age=3600 Expires: Fri, 30 Sep 2022 10:20:00 GMT Location: https://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl Content-Security-Policy: upgrade-insecure-requests Server: cloudflare CF-RAY: 752be1544eea0d2e-ARN alt-svc: h3=":443"; ma=86400, h3-29=":443"; ma=86400 Changing the links in the documents to be https, and avoid the redirect, doesn't help unfortunately since xsltproc can't download assets over https. The lack of https support in libxml2 has been reported, and patches submitted, a long time ago [1] but there is still a lack of https support. Looking around for other mirrors I only managed to find cdn.dookbook.org, which just like Sourceforge does a 301 redirect. Installing the stylesheets locally as we document solves the issue of course, but maybe it's time to move to using --nonet as we discussed in [0] and require the stylesheets locally? It's a shame that casual contributions require a big investment in installation, but it seems hard to get around. -- Daniel Gustafsson https://vmware.com/ [0] https://www.postgresql.org/message-id/flat/e2ee6b76-2d96-408a-b961-cae47d1a8...@yesql.se [1] https://mail.gnome.org/archives/xml/2007-March/msg00087.html