4. If |expression| is an <a>ASCII case-insensitive</a> match for "`'self'`",

return "`Matches`" if one or more of the following conditions is met:

1. |origin| is the same as |url|'s <a for="url">origin</a>

1. |origin| and |url|'s [=url/origin=] are [=same origin=]

2. |origin|'s {{URL/host}} is the same as |url|'s {{URL/host}},

|origin|'s {{URL/port}} and |url|'s {{URL/port}} are either the same