After extension was granted host permission requested with `browser.permissions.request`, everything works as expected, but after browser restart those permissions are lost. This affects both manifest v2 and v3 extension. API permissions (like `tabs`) work as expected and are persisted between browser restarts Minimal extension with reproduction: https://github.com/OlegWock/webkit-webext-bug-repro (all related code located in extension's popup)
<rdar://problem/113515767>