> Is that a common thing for software to be marked as "available for Linux" but only supported for 2 flavours?
Yes, because it keeps the support matrix smaller. As much as people like to think “Linux is Linux is Linux”, there’s all sorts of subtle and not-so-subtle system and library-level differences between distributions that can cause software to not work properly. IBM can’t and won’t test against every single distribution nor will they support their software running on whatever obscure distribution someone decides to use.
Yes, because it keeps the support matrix smaller. As much as people like to think “Linux is Linux is Linux”, there’s all sorts of subtle and not-so-subtle system and library-level differences between distributions that can cause software to not work properly. IBM can’t and won’t test against every single distribution nor will they support their software running on whatever obscure distribution someone decides to use.