Hi @evankoh,
For t-bill that is not mature, when you click onto the SBILL. It will shows the current position where information P&L will be display.
https://stocks.cafe/stock/summary/BS23120A/sbill%3Abs23120a?exchange=SBILL
Once the t-bill is mature, when you click on it. it will not show any information like Closed position.
https://stocks.cafe/stock/summary/BS23108A/sbill%3Abs23108a?exchange=SBILL
I think the behaviour is the same as stock but the only different is for Stock, there is a user tab where it will display summary of closed position where P/L is computed.
We have similar user tab for SSB.