>  a simple comma separated list of names (I think)

There's an "advanced" version with affiliations – details at https://arxiv.org/help/prep#author.

May be non-trivial as they ask just the institution name, and not the address (not sure if those two are kept in separate JSON fields?).

Institution is a single JSON line with the address but fro 99% of them up to the first comma is the institution ..

my ticket branch now has  --mode=arxiv  eg.

{{ python3 $TEXMFHOME/../bin/db2authors.py --mode arxiv}}
 

it currently does the text author list like:

William O'Mullane and Frossie Economou and Kian-Tat Lim and Fritz Mueller and Tim Jenness and K.~Simon Krughoff and Leanne~P. Guy and Gregory~P. Dubois-Felsmann and Ian~S. Sullivan

ok complete

Authors:William O'Mullane(1) and Frossie Economou(1) and Kian-Tat Lim(2) and Fritz Mueller(2) and Tim Jenness(1) and K.~Simon Krughoff(1) and Leanne~P. Guy(1) and Gregory~P. Dubois-Felsmann(3) and Ian~S. Sullivan(4)
((1) Rubin Observatory Project Office, (1) Rubin Observatory Project Office, (2) SLAC National Accelerator Laboratory, (2) SLAC National Accelerator Laboratory, (2) Rubin Observatory Project Office, (2) Rubin Observatory Project Office, (2) Rubin Observatory Project Office, (3) IPAC, (4) University of Washington)