The fund balance is the result of what has posted to the account (net surplus/deficit + manual JEs + balance rolled forward). The post revenues & expenses process of year-end processing is posting the balances of the revenue and expense accounts into the fund balance account. The roll forward process will roll the ending balance into the new year as well. So, when you look at the fund balance it is made up of:

Beginning Balance (from roll forward) + NSD (from post rev & exp) + manual JEs

You can run the Account Detail report (ACDTL) to see what transactions have been post to any of these accounts.
1.  From the Report Manager select Module General Ledger, and select Category Transaction Reports.
2.  Highlight ACDTL Account Detail report and click Produce.
3.  Type in the account number or mask and select the date range.
4.  Amount range should be All.
5.  Journals should be All.
6.  Include Periods should be All.
7.  Do not Include/Exclude any attributes.
8.  Click OK to run the report.

Beginning and ending balances for the accounts selected are not shown in the Account Detail Report.  This report is designed as an analysis tool to filter specific transactions.  The totals returned by this report are simply for the transactions retrieved, which is generally not the balance of the account.