The standard reports, all built from the same journal lines.
Drafts appear in no report
Reports count posted entries only. However complete a draft looks, it is absent from the trial balance, the profit and loss, and the balance sheet.
So when a figure is missing from a report, first check whether its entry was posted or left as a draft.
A reversed entry is neutralised, not removed
A reversed entry and the entry that reversed it both appear in reports, and their effects cancel exactly.
Which means the general ledger shows two lines that look like duplicates. That is correct — removing them would change the history.
The sub-ledger reconciliation report
This compares a control account's balance against an independent sum of the same information in the module that owns it: receivables against invoices, payables against bills, inventory against stock.
When those two disagree, something did not post or was entered by hand. This report is the only place that surfaces it.
Figures are in the base currency
Journal lines are always in the site's base currency. A currency shown on an entry's header describes the original transaction; it is not the unit the report is built in.
The VAT report is output-side only
It totals tax charged on sales. Tax paid on purchases is not in it, because there is no mechanism for recording that as recoverable.