3GPP 21.900 v20.0.0 — the document's own text
7.6 WEB and FTP services
Taught in 15. Reading either body's paper trail from a cold start (How standards actually get made, in depth), 7. Reading either body's paper trail yourself (How standards actually get made, overview).
The 3GPP website (https://www.3gpp.org) and portal (https://portal.3gpp.org) provide up-to-date information on specification work, such as: meeting calendars, meeting minutes, meeting documents and latest specifications. FTP links to file server areas of each TSG and WG can be found via the 3GPP web pages.