Architecture specific libraries/runtime support

Ubuntu 26.04 is releasing soon and will both be an LTS as well as the first version where they've rebuilt "all" packages to have x86-64-v3 variants where possible. This is detailed a bit here and in related discussions:

Its worth noting that they call out that most packages only see a 1% or less gain to real world performance and this should not be particularly impactful to .NET, particularly for JIT scenarios where we are already targeting the "current hardware". However, this does seem like an area where it would be pertinent to confirm that we also playing into Ubuntu's new ecosystem if that is appropriate and that any customizations they may be doing for the x86-64-v3 build of .NET (assuming they have one) doesn't interfere with our deployment mechanisms (NAOT, R2R, self-contained, etc).

It may also be interesting to have a discussion on if there is anything we want to do here for NuGet packages in order to support similar "architecture variant" deployments on our end, similar to how we have "rid specific tools" now: . This may become more impactful with bigger architectural features like APX on xarch or SVE on Arm64.