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It means you receive the tokens over 4 transactions. For example it is common 28 days 4 transactions, this is roughly 4 weeks with 25% unstaked each week.

I think it means the number of transactions needed to unstake the token. If a token unstakes in 28 days over 4; then you receive a transaction with the unstaking value once every 4 days.

thx now I got it, it would be 25% every 7 days in the example.