Not that it answers your question, but the move happened in 2020 to "hire more easily, act more swiftly, and pursue ideas that were previously not possible".
Judging from the side it seems like there aren't a lot of developers and the current few have their favorite subsystems, those get almost all of the attention. The rest is kept as-is and does not progress. I also don't know if there's a trivial way to find how many external contributions they get from BugZilla, if they even get any?
Total mail UI/UX overhaul, total backend overhaul allowing implementation of new protocols (first new protocol was Exchange), an Android app and monthly release cadence vs yearly. And that's just to name the ones that immediately come to mind. Have plenty of users yelling at us for changing too much.
Just in case you need sources: Kagi is using [1] Yandex and paying them as of June 2025. This is a long-standing position, which was also voiced [2] in November 2024.
Regarding Yandex. The founder sold [3] the assets (seemingly including the index and Yandex trademark) to VK (Mail.ru) in 2022. VK are known supporters of the war [4]. The founder subsequently renamed [5] his original company to Nebius Group and pivoted towards compute for AI.
I was browsing through the issues of extrepo and found deb-get, seems pretty useful too:
> deb-get makes it easy to install and update .debs published in 3rd party apt repositories or made available via direct download on websites or GitHub release pages.
https://github.com/Zetaphor/whatcable-linux
https://github.com/abrauchli/usbee