Same here, but it shows downloaded and I am unable to download....hmmmmm
If i install this, will i be able to do update from this candidate to maybe the final version (if this is not the final)?
This seed will not be the GM. It's likely a GM candidate. The build number still has a letter after it. The only publicly shipping Mac OS with a letter at the end are machine specific builds that come loaded on new hardware when it's released mid-OS cycle. The next point upgrade always merges the OS back together. This will not be the GM. Guaranteed.
15A282b
15=Major (kernel) version
A=First point release (x.x.0)
282 = 282nd build in the above build hierarchy
b = This build was made for a specific target audience (AKA developer beta, public beta, internal beta, machine specific, etc.) There does not appear to be a specific meaning to the letters (b might be developer beta this time but might mean something totally different next time). No letter = public release.
They've always followed this convention, all the way back to 10.0.0
It wasn't for yosemite though. The final GM for yosemite was not the same build number as first public release. And no delta update was available for that. One had to do it with the full installer.
It is most definitely not going to be identical to the release version, I agree. With each recent release since Snow Leopard, I've always made a bootable flash drive so I can upgrade all of my macs in addition to using it for recovery. Last year's GM image produced a volume called "Install OS X Yosemite". On creating a bootable drive from the new build, (using the embedded createinstallmedia tool) the volume name of the resulting drive is "Install OS X El Capitan GM Candidate".This seed will not be the GM. It's likely a GM candidate.