olemus
URI nimestruktuuri ülatase, üladomeeni analoog
= the top level of the URI naming scheme, the analog of the top-level domain

näiteid
https://cpp-netlib.org/0.9.3/_images/ftp_uri.png
https://facingissuesonitcom.files.wordpress.com/2019/11/data-uri-schema.jpg

ülevaateid
http://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml
https://greenbytes.de/tech/webdav/rfc3986.pdf
https://en.wikipedia.org/wiki/List_of_URI_schemes
https://www.w3.org/wiki/UriSchemes

standardid
https://www.ietf.org/rfc/rfc3986.txt (see: Chapter 3)
https://datatracker.ietf.org/doc/html/rfc7595