English Bus/Financial Accounting

Could you help me clarify the meaning of one of the sentences below?
Here's the context:
Borrowings incorporating embedded derivatives

Borrowings incorporating embedded derivatives represent hybrid financial instruments. The Group has borrowings under Total Return Swap (TRS) transactions which are classified as hybrid instrument incorporating a host debt instrument and TRS embedded derivative. An embedded derivative is separated from the host debt contract and accounted for as derivative if its economic characteristics are not closely related to the economic characteristics of the host debt instrument. In this case, the host debt instrument is also separately accounted for as disclosed in the accounting policies mentioned above (borrowings). In case where the Group is not able to measure the embedded derivative separately either at inception or at subsequent financial reporting date, then the entire hybrid instrument is accounted for as held for trading. Financial liabilities held for trading are re-measured at fair value and any fair value changes are recognised through the income statement. Any liability that is linked to **and must be settled by delivery of an unquoted equity instrument whose fair value cannot be reliably measured is measured at cost.

Any liability that is linked to **what**?
What is the liability linked to?