Without full/strict Site Isolation, subframe entries in Chrome Task Manager may show misleading entries.  For example:
- "Subframe: https://foo.com" may also host frames from bar.com
- "Subframe: https://unisolated.invalid" may be shown in the future if we proceed with https://crrev.com/c/1252534 (for  issue 512560  and issue 787576)

OTOH, the only Chrome platform without strict site isolation is Android, and it doesn't have a task manager.  Therefore this issue only applies to desktop platforms opted out of strict site isolation (by users / enterprise policy / non-Chrome //content embedders).