An overview from 2011 of the to-be-implemented FNS. [2]

Official site for AIXM, the interchange model used by FNS. It has a Github account (!) with resources including XLST templates. [4]

ICAO (International Civil Aviation Org.) 2017 "Information Paper" about FAA's migration from USNS to FNS. [5] Kind of fluffy, but a few interesting details. As of 2017, FNS was handling 80% of NOTAMS generated.

Wait, there's a new new thing. [6] (2022) System Wide Information Management (SWIM) "is the Digital Data-Sharing backbone of NextGen" [7], and NOTAMS are now available through it.

Finally, a recent National Airspace "Enterprise Architecture Infrastructure Roadmap" [8] has link to a ppt document which has an annoying number of external links that 404 (I just keep telling LibreOffice "OK" and it eventually loaded). edit: Slide 28 just says "FNS Sustainment" for 2021-2024, and USNS is a dotted line petering off in 2025.

[1] https://www.aviationtoday.com/2019/11/18/faa-looks-finish-consolidating-notams-one-system/

[2] https://www.aixm.aero/sites/aixm.aero/files/imce/library/ATIEC_2011_08/13_day1_notam_news_and_demo.pdf

[3] https://www.aixm.aero/

[4] https://github.com/aixm

[5] https://www.icao.int/NACC/Documents/Meetings/2017/AIMFPL/AIM-FPL-AIDC-IP02.pdf

[6] https://www.faa.gov/about/initiatives/notam

[7] https://www.faa.gov/air_traffic/technology/swim/overview/

[8] https://www.faa.gov/nextgen/nas-enterprise-architecture-infrastructure-roadmaps