Uri Type
A general URI as defined by RFC 3986, used in the AT Protocol for links and references.
Must have a valid scheme (starting with a letter, followed by letters, digits, +, -, or .)
followed by : and a non-empty scheme-specific part with no whitespace.
Maximum length is 8192 characters.
This performs basic syntactic validation only. Valid scheme examples include
https, dns, at, did, and content-type.
See https://www.rfc-editor.org/rfc/rfc3986 for the full URI specification.