Opens the browser-backed tier, or undefined when Cache Storage is absent or refuses to open (private browsing, storage disabled). Callers treat undefined as "no tier": every lookup is a miss and nothing is published.
undefined
Opens the browser-backed tier, or
undefinedwhen Cache Storage is absent or refuses to open (private browsing, storage disabled). Callers treatundefinedas "no tier": every lookup is a miss and nothing is published.