Yup, that’s what I thought. Right now all three entries will start Qubes OS with kernel v5.10.90.
The first is the default, which will boot the latest version. The second is the actual latest version, so in this particular state entry 1 & 2 are the same. Entry 3 sounds different, but I have to admit I don’t actually know what the “config” part in it means. Maybe someone else can elaborate.
As new kernel versions are released and you update dom0, these will show up here and also heads will prompt you to sign this new entries. So when you update dom0 it is important for you to watch the result and see if dom0 actually received a new kernel version. Otherwise you will freak the first time heads alerts you to a change in the boot config and you might think you’ve been hacked when in fact you simply upgraded.
The first entry will always point to the latest version so in most cases you just want to make it the heads default for booting. Only if that entry gives you trouble would you choose another one.
No doubt that sounds complicated right now, but once you did it a few times it’ll become routine. Again the important part is that you keep an eye on the update so you are not surprised about heads warning you. On the flip side: if heads is warning you and you didn’t install an upgrade … that’s the case you have it for. Then someone or something else tampered with your boot config.