Nikola Tesla Museum, Belgrade (tesla-museum.org), 2026-10-08

Found

Archive page [web: https://tesla-museum.org/en/legacy/archive/]: Tesla's personal archive (documents, manuscripts, scientific notes, calculations, drawings, letters) totals 163,911 call numbers, 1856-1943, in 548 boxes, catalogued in seven units: Identity Documents; Legal Affairs & Finance; Correspondence; Activity; Plans and Drawings; Photo Material; Varia. No online document viewer was found on the page; the site has a "Library Inventory Search".
Writings page [web: https://tesla-museum.org/en/nikola-tesla-2/writings/]: a numbered bibliography of Tesla's articles from 1887 (e.g. no. 4, "Erscheinungen bei Wechselströmen mit hoher Wechselzahl", E.T.Z. Berlin, 5 June 1891; no. 12, "Les vibrations électriques fréquentes", Moniteur industriel, Paris, 1893; no. 14, "Earth Electricity to Kill Monopoly", The World, 8 March 1896). Bibliographic only; no texts.
Bears on priority 1 and 4: the Belgrade archive is where the post-1943 papers went (the "Legal Affairs & Finance" and "Activity" units would hold Wardenclyffe and turbine business records; "Plans and Drawings" any teleforce drawings). It is the deciding record for claim 6's question whether the papers held "nothing of significant value". Access needs the museum (owner action).
Not reached: the Library Inventory Search, the Press Clippings collection, the 1896 "Earth Electricity to Kill Monopoly" text (an early statement of earth-power ideas, before Colorado).