Create web shortcuts for custom URLs that use RegEx (or our syntax) in the URL to make them available only when the opened website's URL matches the Custom URL.

For Example, if one sets this custom URL for a web shortcut - https://twitter.com/<<string>>/status/<<number>>

The shortcut will work only on tweets pages. <<string>> means any string of varied lengths can be there in its place and <<number>> means only numbers can be there. And when one opens a tweet the URL matches because in the place of <<string>> there's the username and in the place of <<number>> there's Tweet's ID.