Understanding the acclerator logs

Hi,

Please refer following log, I am trying to undertand what is happening on each line for asset Assets/xxy@special.fbx

Start importing Assets/xxy@special.fbx using Guid(XXXXXXXXXXX) Importer(-1,00000000000000000000000000000000)
Keyframe reduction: Ratio: 30.938417%; Time: 0.000194s;
Done importing asset: ‘Assets/xxy@special.fbx’ (target hash: ‘XXXXXXXXXXXTargetHash’) in 0.292136 seconds
What is importer here and what is Target Hash ?

RemoteAssetCache::AddArtifactToCacheServer - artifactKey=‘Guid(XXXXXXXXXXX) Importer(-1,00000000000000000000000000000000)’ Target hash=‘XXXXXXXXXXXTargetHash’ Key (and library path)=‘Library/Artifacts/d6/XXXXXXXXXXXLibKey’
RemoteAssetCache - Upload - Artifact - success:true, namespace:XXXXXXXXXXXNameSpace, key:XXXXXXXXXXXLibKey
RemoteAssetCache - Upload - Artifact - success:true, namespace:XXXXXXXXXXXNameSpace, key:XXXXXXXXXXXLibKey2
Even though here it shows upload status to be true, but when I enquire using key XXXXXXXXXXXLibKey2, it says key not found. I checked after few hours so it should have refreshed in cache server. I use following command

>unity-accelerator cache get IPAddress XXXXXXXXXXXNameSpace XXXXXXXXXXXLibKey2

RemoteAssetCache - Download - Metadata - success:true, namespace:XXXXXXXXXXXNameSpace, key:XXXXXXXXXXXLibKey3
RemoteAssetCache - Upload - Metadata - success:true, namespace:XXXXXXXXXXXNameSpace, key:XXXXXXXXXXXLibKey3

Here when I enquire using key XXXXXXXXXXXLibKey3, it dumps obfuscated text meaning key is present.
So why artifact is not present but metadata is, even upload status is true for artifact ?
What is metadata and how it is related to Artifact. ?

I met the same question!