Subject: Re: Bug #1002840 — Confirmed on Debian 13 (Trixie): official APT
DEP-11 metadata references missing screenshots; newer generator metadata
works
Hello,
I can confirm that this issue is reproducible on Debian 13 (Trixie) as of
October 11–12, 2026.
I investigated the problem after noticing that KDE Discover displayed
broken screenshot placeholders for essentially every application, despite
successfully loading application descriptions, ratings, and other metadata.
The investigation indicates that Debian's official stable APT repository is
distributing outdated DEP-11 metadata whose screenshot references no longer
exist on Debian's AppStream servers.
Importantly, this does not appear to be caused by a stale local APT cache.
The metadata currently distributed by Debian's official repository is
itself outdated relative to the AppStream generator.
1. SYSTEM INFORMATION
=====================
Distribution: Debian GNU/Linux 13 (Trixie)
Desktop environment: KDE Plasma
KDE Discover: 6.3.6-1
AppStream: 1.0.5-1
Architecture: amd64
Repository: deb.debian.org, trixie/main
Investigation date: October 11–12, 2026
AppStream reports a populated software catalog:
AppStream Status:
Version: 1.0.5
OS metadata sources:
Software catalog data
Group: os-catalog
/var/lib/swcatalog/yaml
• YAML: 4
/var/lib/swcatalog/icons
• Iconsets:
debian-trixie-main
debian-trixie-contrib
debian-trixie-non-free-firmware
debian-trixie-non-free
Summary:
✔ We have information on 2626 software components.
The system's AppStream metadata was refreshed successfully, but this did
not resolve the missing screenshots.
2. KDE DISCOVER REQUESTS NONEXISTENT SCREENSHOT URLS
===================================================
When launching Discover from a terminal and viewing GIMP, the following
errors appear:
QML QQuickImage: Error transferring
https://appstream.debian.org/media/trixie/org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/image-1_orig.png
- server replied:
Similar errors occur for all four GIMP screenshots and their thumbnail
variants.
Testing the URL directly:
curl -IL --max-time 15 \
'
https://appstream.debian.org/media/trixie/org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/image-1_orig.png
'
Result:
HTTP/2 404
server: Apache
The thumbnail variant also returns HTTP 404:
https://appstream.debian.org/media/trixie/org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/[email protected]
3. VERIFIED AGAINST FOUR DEBIAN SERVER ADDRESSES
================================================
To rule out DNS filtering, resolver problems, or a single out-of-sync
server, I tested the same URL against all four IPv4 addresses returned by
public DNS for appstream.debian.org.
The tests used curl's --resolve option to preserve the correct HTTPS
hostname while selecting each server directly.
Results:
194.177.211.216 HTTP 404
128.31.0.62 HTTP 404
130.89.148.77 HTTP 404
194.71.11.122 HTTP 404
All four servers returned HTTP 404.
Local DNS resolution also returned the same addresses as Cloudflare
(1.1.1.1) and Google (8.8.8.8).
This makes local DNS filtering or an individual server synchronization
problem unlikely.
4. BROKEN URLS ORIGINATE IN DEBIAN'S OFFICIAL DEP-11 METADATA
=============================================================
The installed DEP-11 metadata is located at:
/var/lib/apt/lists/deb.debian.org_debian_dists_trixie_main_dep11_Components-amd64.yml.gz
The corresponding AppStream catalog entry is accessed through:
/var/lib/swcatalog/yaml/
Examining the compressed YAML confirms that the GIMP entry contains the
exact screenshot paths Discover attempts to download:
Screenshots:
- default: true
thumbnails:
- url:
org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/[email protected]
width: 1248
height: 702
source-image:
url:
org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/image-1_orig.png
width: 1920
height: 1080
The catalog header specifies:
---
File: DEP-11
Version: '1.0'
Origin: debian-trixie-main
MediaBaseUrl: https://appstream.debian.org/media/trixie
Time: 20250808T201448
Thus, the screenshot URLs are not being incorrectly constructed by KDE
Discover. They originate directly from Debian's distributed DEP-11 metadata.
5. OFFICIAL APT REPOSITORY STILL DISTRIBUTES AUGUST 2025 METADATA
=================================================================
The local DEP-11 file was downloaded on October 11, 2026.
Its filesystem timestamps show:
Modify: 2025-08-08 16:14:57 -0400
Change: 2026-10-11 15:14:37 -0400
Birth: 2026-10-11 15:14:36 -0400
The catalog header identifies its generation time as August 8, 2025.
To verify whether this was merely a stale local copy, I queried Debian's
official repository directly:
curl -sSI \
'
https://deb.debian.org/debian/dists/trixie/main/dep11/Components-amd64.yml.gz
'
Result:
HTTP/2 200
last-modified: Fri, 08 Aug 2025 20:14:49 GMT
etag: "7ac722-63be039d4a02b"
content-length: 8046370
The remote file's timestamp and size match the locally installed catalog.
Therefore, a freshly updated Debian 13 system is still receiving DEP-11
metadata generated in August 2025.
6. DEBIAN'S APPSTREAM GENERATOR PROVIDES NEWER METADATA
=======================================================
I then checked the catalog distributed directly by Debian's AppStream
generator:
curl -sSI \
'https://appstream.debian.org/data/trixie/main/Components-amd64.yml.gz'
Result:
HTTP/2 200
last-modified: Sat, 12 Sep 2026 14:11:19 GMT
etag: "7b1f4e-65b49c65f8737"
content-length: 8068942
Comparison:
Source Last modified Size
------------------------------------------------------
Official Debian APT repo 2025-08-08 8,046,370 bytes
AppStream generator 2026-09-12 8,068,942 bytes
The AppStream generator has produced substantially newer metadata, but the
stable APT repository continues distributing the older catalog.
7. NEWER METADATA REFERENCES WORKING SCREENSHOTS
================================================
I downloaded the newer catalog directly:
curl -fL \
'https://appstream.debian.org/data/trixie/main/Components-amd64.yml.gz' \
-o /tmp/trixie-appstream-new.yml.gz
Examining its GIMP entry reveals different screenshot paths:
org/gimp/GIMP/c34d2bf00231e1cf30bb916c4bd19be7/screenshots/image-1_orig.png
org/gimp/GIMP/c34d2bf00231e1cf30bb916c4bd19be7/screenshots/image-2_orig.png
org/gimp/GIMP/c34d2bf00231e1cf30bb916c4bd19be7/screenshots/image-3_orig.png
org/gimp/GIMP/c34d2bf00231e1cf30bb916c4bd19be7/screenshots/image-4_orig.png
The directory hash differs from the one distributed through APT:
APT metadata (2025):
81aa8be6edc018b9d60a2f0cd75bd113
AppStream generator (2026):
c34d2bf00231e1cf30bb916c4bd19be7
Testing the newer screenshot URL:
curl -IL --max-time 15 \
'
https://appstream.debian.org/media/trixie/org/gimp/GIMP/c34d2bf00231e1cf30bb916c4bd19be7/screenshots/image-1_orig.png
'
Result:
HTTP/2 200
last-modified: Sat, 12 Sep 2026 14:10:53 GMT
content-length: 1366764
content-type: image/png
server: Apache
The screenshot referenced by the newer metadata exists and is downloadable,
whereas the screenshot referenced by the official APT metadata returns HTTP
404.
This demonstrates a direct relationship between the outdated repository
metadata and the missing screenshots.
8. REPRODUCTION PROCEDURE
=========================
On a Debian 13 system using the official Trixie repositories:
1. Run sudo apt update.
2. Install KDE Discover and AppStream if not already installed.
3. Open Discover and navigate to GIMP.
4. Observe that application information loads, but screenshots are missing.
5. Inspect the GIMP screenshot URLs in the DEP-11 catalog under
/var/lib/apt/lists/.
6. Request one of those URLs using curl and observe HTTP 404.
7. Download the newer catalog from the AppStream generator.
8. Extract its GIMP screenshot URL and observe that it returns HTTP 200.
Alternatively, the underlying metadata discrepancy can be reproduced
without KDE Discover by comparing the two catalog sources and testing their
respective screenshot URLs.
9. SUSPECTED ROOT CAUSE
=======================
The evidence suggests that Debian's AppStream generator continues updating
Trixie metadata and associated screenshot files, while the official Debian
Stable APT repository is not receiving the regenerated DEP-11 catalogs.
As screenshot references change, the older catalog eventually points to
image files that are no longer available.
This appears consistent with the issue described in this bug report.
The primary problem does not appear to be KDE Discover, local DNS, TLS
certificates, or an outdated local cache.
10. REQUEST FOR MAINTAINER INVESTIGATION
========================================
Could the maintainers please investigate whether updated DEP-11 metadata is
being imported into the Debian Stable archive as intended?
In particular:
- Is it expected that Trixie's official APT repository still distributes
DEP-11 metadata generated on August 8, 2025?
- Should the newer catalog generated on September 12, 2026, have been
propagated to the Stable repository?
- Is the apparent lack of synchronization related to the archive import
configuration discussed earlier in this bug?
- Can the newer DEP-11 metadata be published to Stable without requiring a
Debian point release?
I have not manually replaced the system's APT-managed metadata or installed
a local override. The system remains in its standard repository-managed
configuration.
I hope these findings help identify and reproduce the underlying issue.
Thank you for your work on Debian and AppStream.
On Fri, 18 Sep 2026 15:33:35 +0200 Matthias Klumpp <[email protected]> wrote:
> Am Fr., 18. Sept. 2026 um 14:33 Uhr schrieb Marcel Partap <[email protected]
>:
> >
> > This seemingly never has been resolved and the most prevalent linux app
> > store (to my knowledge, I only use aptitude 🤩) `gnome-software` looks
> > direly broken on a current trixie live system.. log shows loads of
> >
> > > Screenshot download
> > > '
https://appstream.debian.org/media/trixie/org/gnome/TwentyFortyEight/ff33fadaa7c0dff69bd6e4c6a7b9c8d5/screenshots/[email protected]
'
> > > failed with status code '404': Not Found
> > [...]
> >
> > If that script not including `stable` is in fact the source of the
> > problem, can someone privileged to change it please fix it to boost up
> > debian's reputation amongst linux noobs that tiny bit? 😂
>
> Your metadata must be ancient... Did you run an `apt update` recently?
> Can you provide the output of `appstreamcli status`?
>
> If you remove GNOME Software's own cache, does that solve the issue?
> ```
> gnome-software --quit
> rm -r ~/.cache/gnome-software
> gnome-software --verbose
> ```
>
> I can't reproduce this here, so I assume you must have stale metadata
> somehow (and that might indeed be some kind of bug, because this data
> should update via APT).
>
> Best,
> Matthias
>
>
![https://appstream.debian.org/media/trixie/org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/[email protected]](https://appstream.debian.org/media/trixie/org/gimp/GIMP/81aa8be6edc018b9d60a2f0cd75bd113/screenshots/image-1_1248x...@1.png){kind=link}
![https://appstream.debian.org/media/trixie/org/gnome/TwentyFortyEight/ff33fadaa7c0dff69bd6e4c6a7b9c8d5/screenshots/[email protected]](https://appstream.debian.org/media/trixie/org/gnome/TwentyFortyEight/ff33fadaa7c0dff69bd6e4c6a7b9c8d5/screenshots/image-1_224x...@1.png){kind=link}