6.0.4 released at 2021-04-22, 6.1 released at 2021-04-27. Where's 6.0.5 and so on? It's not released. Debian supports its releases for 5 years, not for 5 days.
Debian supports its releases for 5 years, not for 5 days.
Only run Debian here, but to be clear, Debian supports releases for 1 year after the next release, so typically 3 years max.
Debian LTS is handled by a third party, non-debian org, via donations. All packages are not necessarily covered, it's not the Debian securtiy team.
This is important to understand, as LTS depends upon donations to decide what gets secuirty updates. Donors have a say. So for example, you'll see apache, openssl, php updated, but not obscure pacakges.
6.0.0 was released 08.12.2020, with 6.0.4 released at 04.05.2021 as the last patch release in that minor series. That's more than 5 days of support for the 6.0 minor series.
If Debian supports its releases for longer than the upstream projects do, then that's a (perfectly valid) choice of Debian, but I'm assuming that involves maintaining those projects as well, to the standards of Debian's support policies.
AFAIK LTS is for paying customers only. For mortal people there's no LTS, there're only promises that 6.3 is backwards-compatible (but then why people pay for LTS at all).
Qt 6.2.4 was released at 2022-02-17 and it's the last public available 6.2 version. 6.3 was released at 2022-03-16. For paying customers they released 6.2.8 few months ago, for example, but it's not available for everyone else.
I do not expect anything from them and I’m grateful to receive quality open source library for free with current terms as that’s infinitely better than having a proprietary library. I’m just merely trying to understand how Debian deals with thus situation.
That said, of course having upstream patches available for free, as it was in the past, would even be better.