If as far as you know the OP is using a supported release, don't flag as off-topic.
One possible way to interpret our policy is that it's about what release the user is running, and not how they are using it or what software they are using on it. In that case, questions about the common subset of desktop and server software would still be off-topic, once it comes to light that the user installed a desktop system.
The problem with that, as you've observed, is that it's not totally clear how to distinguish between server and desktop installations. You can get to one from the other, pretty easily.
So if the OP is asking about something that is supported past desktop EoL, and their release is still supported on servers, I'd say we should not close it.
If they're asking about server software like Apache, it's likely (though not definite) that they're running Ubuntu Server anyway. We shouldn't assume they're not.
My understanding is that when an LTS release is end-of-life on the desktop but still supported for servers, that means packages are supported that are:
- from the main or restricted repositories (the repos maintained by Canonical)
- does not provide a GUI
- does not need a GUI too run
I remember reading that somewhere. Really, I do. Unfortunately, I cannot find it now. I cannot find any clear explanation for what server-only "extended support" consists of in Ubuntu. This answer suggests my memory may be correct.
Why is this important? Because
if we only support Canonical-maintained software, and act in accordance with gertvdijk's meta-answer, then while the particular question in question would probably be on-topic (git is in main, and was then too), a number of other questions including questions about actual Ubuntu Server installations would be off-topic.
Update: It turns out Git isn't supported in 10.04 Lucid anymore, after all. I suppose we should close this again after all (and perhaps apologize to its OP for the back-and-forth). Before we do, we should discuss if we want to support more than the security team does ...but I can't see how doing so would be in the spirit of our current policy on new EoL release questions.
With that said, the issue of disconnect between whether or not a question is about supported parts of Ubuntu, and whether or not its user is running a supported release, is more relevant than ever given this corrected information about what packages are supported.
I don't consider this an undesirable way to interpret our policy. But we should try to clarify if it is the interpretation we wish to consider correct. (I'd be in favor of this, by the way.)
Hopefully someone can shed light on this. Let's make sure we have a community consensus on how to apply this information. Maybe it would be best to unaccept this answer to make clear that further input is sought (assuming you agree we should seek more).