You can export a bulk list of all of your metrics and definitions in the Report Engine by navigating to the Metric / Dimension Overview.
You can find this by clicking on the 'Client Admin' button in the top right corner:
This will take you to a separate page in the Report Engine where you will be able to choose whether you would like to look at a list of Metrics or Definitions:
This page lists all of your metrics and some metric details like the folder it belongs to (category), Info (description details), prefix, suffix, round, uplift bias and the first two metric definitions.
From this page you can download a csv of this page by clicking on the 'csv' button. You can also use the search bar to in the top right to show only a subset of metrics.
This page lists all of your dimensions and some dimensions details like the folder it belongs to (category), Info (description details), the mapping definition and the mapping result.
From here you can export all of your dimensions or search for a specific subset of dimensions.