Click on the (i) icon located in the top left of a report:

This will bring up the 'Specification' panel which shows you the make-up of the report - its metrics / dimensions / filters / date rage / sorting / limiting options:
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Users can also preview the queries behind the report and see how long each query takes to load.

The 'Filter ancestry' table lets you see how filters are feeding into your report, if they're being inherited from a folder or dashboard filter and any compatibility issues:

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