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CORS - Glossary | MDN
Access-Control-Allow-Origin
Indicates whether the response can be shared.
Access-Control-Allow-Credentials
Indicates whether or not the response to the request can be exposed when the credentials flag is true.
Used in response to a preflight request to indicate which HTTP headers can be used when making the actual request.
Access-Control-Allow-Methods
Specifies the method or methods allowed when accessing the resource in response to a preflight request.
Indicates which headers can be exposed as part of the response by listing their names.
Access-Control-Max-Age
Indicates how long the results of a preflight request can be cached.
Used when issuing a preflight request to let the server know which HTTP headers will be used when the actual request is made.
Access-Control-Request-Method
Used when issuing a preflight request to let the server know which HTTP method will be used when the actual request is made.
Origin
Indicates where a fetch originates from.
Timing-Allow-Origin
Specifies origins that are allowed to see values of attributes retrieved via features of the Resource Timing API , which would otherwise be reported as zero due to cross-origin restrictions.
