This directory contains tests for the Async Cookies API.
A simple origin cookie is a cookie named with the __Host- prefix which is always secure-flagged, always implicit-domain, always /-scoped, and hence always unambiguous in the cookie jar serialization and origin-scoped. It can be treated as a simple key/value pair.
"LEGACY" in a cookie name here means it is an old-style unprefixed cookie name, so you can't tell e.g. whether it is Secure-flagged or /-pathed just by looking at it, and its flags, domain and path may vary even in a single cookie jar serialization leading to apparent duplicate entries, ambiguities, and complexity (i.e. it cannot be treated as a simple key/value pair.)
Cookie names used in the tests are intended to be realistic. Traditional session cookie names are typically all-upper-case for broad framework compatibility. The more modern "__Host-" prefix has only one allowed casing. An expected upgrade path from traditional “legacy” cookie names to simple origin cookie names is simply to prefix the traditional name with the "__Host-" prefix.
Many of the used cookie names are non-ASCII to ensure straightforward internationalization is possible at every API surface. These work in many modern browsers, though not yet all of them.