What does the value listed under "Cap Accrual Amount" represent when setting up a Time Off plan?

The Cap Accrual amount is an editable amount that once reached will halt accruals. You are not able to add more time off manually or pass this limit. 

Note: It is possible to accrue more than this cap amount if the Available Now balance dips below the cap. At this point, you will accrue until the cap is reached again.