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Package libxapian30 is not installed.
Then sudo apt install libxapian30 and since the system is borked from trying to install the -dev package sudo dpkg -r --purge synaptic-build-deps you may want to do that first. This is why I dislike those GUI programs they do nothing to show you how the system works and leaves you unable to solve even the most basic of problems due to this lack of eperience.
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why didn't they at the same time fix synaptic to receive them over https?
Same reason they left it unable to use the new .sources format when they shipped Trixie, they care about their users, it says so in their policies they like to quote so often...
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Exotic non-essential function that nobody really uses and tests?
Yep. Have never used it. In general I don't like the idea of clicking external links in programs that want to connect me to gawd-knows-what.
https://sourceforge.net/projects/vuu-do/ New Vuu-do isos uploaded October 2025!
Vuu-do GNU/Linux, minimal Devuan-based Openbox and Mate systems to build on. Also a max version for OB.
Devuan 5 mate-mini iso, pure Devuan, 100% no-vuu-do.
Devuan 6 version also available for testing.
Please donate to support Devuan and init freedom! https://devuan.org/os/donate
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I have not managed to see a screenshot in Synaptic for a long time (years?). I gave up trying. Best to Google for it separately to find an image for it, if there are any.
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