OptionalasThis attribute is only used when rel="preload" or rel="prefetch" has been set on the <link> element.
It specifies the type of content being loaded by the <link>, which is necessary for request matching,
application of correct content security policy, and setting of correct Accept request header.
Furthermore, rel="preload" uses this as a signal for request prioritization.
OptionalblockingThe blocking attribute indicates that certain operations should be blocked on the fetching of an external resource. The value is an unordered set of unique space-separated tokens, each of which are possible blocking tokens.
OptionalcolorThe color attribute is used with the mask-icon link type.
The attribute must only be specified on link elements that have a rel attribute
that contains the mask-icon keyword.
The value must be a string that matches the CSS <color> production,
defining a suggested color that user agents can use to customize the display
of the icon that the user sees when they pin your site.
OptionalcrossoriginThis enumerated attribute indicates whether CORS must be used when fetching the resource.
CORS-enabled images can be reused in the <canvas> element without being tainted.
OptionalfetchpriorityProvides a hint of the relative priority to use when fetching a preloaded resource.
OptionalhrefThis attribute specifies the URL of the linked resource. A URL can be absolute or relative.
OptionalhreflangThis attribute indicates the language of the linked resource. It is purely advisory. Allowed values are specified by RFC 5646: Tags for Identifying Languages (also known as BCP 47). Use this attribute only if the href attribute is present.
OptionalidThe id global attribute defines a unique identifier (ID) which must be unique in the whole document.
OptionalimagesizesFor rel="preload" and as="image" only, the imagesizes attribute is a sizes attribute that indicates to preload the appropriate resource used by an img element with corresponding values for its srcset and sizes attributes.
OptionalimagesrcsetFor rel="preload" and as="image" only, the imagesrcset attribute is a sourceset attribute that indicates to preload the appropriate resource used by an img element with corresponding values for its srcset and sizes attributes.
OptionalintegrityContains inline metadata — a base64-encoded cryptographic hash of the resource (file) you're telling the browser to fetch. The browser can use this to verify that the fetched resource has been delivered free of unexpected manipulation.
OptionalmediaThis attribute specifies the media that the linked resource applies to. Its value must be a media type / media query. This attribute is mainly useful when linking to external stylesheets — it allows the user agent to pick the best adapted one for the device it runs on.
OptionalnonceA cryptographic nonce ("number used once") which can be used by Content Security Policy to determine whether or not a given fetch will be allowed to proceed.
OptionalprefetchIdentifies a resource that might be required by the next navigation and that the user agent should retrieve it. This allows the user agent to respond faster when the resource is requested in the future.
OptionalreferrerpolicyA string indicating which referrer to use when fetching the resource.
OptionalrelThis attribute names a relationship of the linked document to the current document. The attribute must be a space-separated list of link type values.
OptionalsizesThis attribute defines the sizes of the icons for visual media contained in the resource. It must be present only if the rel contains a value of icon or a non-standard type such as Apple's apple-touch-icon.
OptionaltitleThe title attribute has special semantics on the <link> element.
When used on a <link rel="stylesheet"> it defines a default or an alternate stylesheet.
OptionaltypeThis attribute is used to define the type of the content linked to. The value of the attribute should be a MIME type such as text/html, text/css, and so on. The common use of this attribute is to define the type of stylesheet being referenced (such as text/css), but given that CSS is the only stylesheet language used on the web, not only is it possible to omit the type attribute, but is actually now recommended practice. It is also used on rel="preload" link types, to make sure the browser only downloads file types that it supports.
From T, pick a set of properties whose keys are in the union K