means its a direct transaction (i.e that was the previous t…

means its a direct transaction (i.e that was the previous transaction or the next transaction). it's what makes the really long chains in the middle, just about all of which are the ones you asked about

https://twetch.app/t/eb311ac5138c65218f2881d06f2e458731c26715eaf09227bc84ea699746e3f1