I note after double-checking that, despite bookworm repos [1] providing only Packages.xz and Packages.gz and not Packages, apt does really seem to check only for Packages in my case:
root@debian:~# apt update Hit:1 http://security.debian.org/debian-security bookworm-security InRelease Hit:2 http://deb.debian.org/debian bookworm InRelease Ign:3 https://gitlab.com/api/v4/projects/xen-project%2Fxen-guest-agent/packages/generic/deb-amd64 ci/ InRelease Hit:4 https://gitlab.com/api/v4/projects/xen-project%2Fxen-guest-agent/packages/generic/deb-amd64 ci/ Release Ign:5 https://gitlab.com/api/v4/projects/xen-project%2Fxen-guest-agent/packages/generic/deb-amd64 ci/ Release.gpg Reading package lists... Done Building dependency tree... Done Reading state information... Done 77 packages can be upgraded. Run 'apt list --upgradable' to see them. W: Skipping acquire of configured file 'Packages' as repository 'https://gitlab.com/api/v4/projects/xen-project%2Fxen-guest-agent/packages/generic/deb-amd64 ci/ InRelease' does not seem to provide it (sources.list entry misspelt?) root@debian:~# curl https://gitlab.com/api/v4/projects/xen-project%2Fxen-guest-agent/packages/generic/deb-amd64/ci/Release Date: Wed, 13 Dec 2023 09:55:54 +0000 Description: xen-guest-agent CI packages Label: xen-guest-agent-ci Suite: ci MD5Sum: 4bbd32da77623285b8a54ef926a1f028 277 Contents-amd64.gz 9c8c7743a78d4c850fbdffac54c5e159 340 Contents-amd64.xz 557f3042ec38f51a838d518739ecf4c2 925 Packages.gz a3b82abf0ab81c4d5f829ec631c9deb8 1008 Packages.xz SHA1: [1] http://ftp.debian.org/debian/dists/bookworm/main/binary-all/
