Interfund accounts are the same as due to/from accounts.  They are used to ensure each fund is in balance with each posting.  Therefore, if the fund is not in balance between the debits and credits when it is posted to the GL, the system will automatically create transactions to these interfund accounts to ensure each fund is in balance with the posting. 

Their balances would be the debits and credits posted to them to keep the funds in balance when the posting crosses funds. 

The interfund accounts follow the same rules as other accounts within the same category.  If the interfund account is set as a liability, then the account's balance will roll forward to the next year at year end processing.  If the interfund account is setup as an expense or revenue, then it will post into the fund balance.  It would be up to each client to determine what type of account the interfund needs to be.

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.