Ultimately, there is only a monetary claim on the governments: What is its nature?

Central banks belong to governments, which means that the only balance sheet of interest is the consolidated balance sheet of the central bank and the government. This balance sheet shows that the government (in the broad sense) has two debts: bond debt and monetary debt. It is important to note that: The government's monetary debt consists of banknotes and banks' reserves at the central bank, but that when there is quantitative easing, banks' reserves at the central bank also result from purchases of bonds from non-bank economic agents; The government's bond debt (sovereign debt) is considered risk-free because the government can raise taxes to repay it, but this is increasingly difficult, and in particular because this debt can be monetised by the central bank. We then see that economic agents have a bond claim and a monetary claim on the government, but that the bond claim is accepted because it can be transformed into a monetary claim. Ultimately, the only thing that matters is economic agents' acceptance of a monetary claim on the government. If this acceptance disappears, everything collapses, including the government's ability to have a bond debt.