For an overview of data about the event available from Chess-results.com, see the first post from this month, Lenderman, Rapport Take Reykjavik. For an overview of data available from Chessbomb.com, see More on the Fischer Random Cup. In that post I wrote,
How about some games? Since 100 players participated, 50 games were played per round -- nine rounds should give 450 games for the tournament. The page Fischer Random Cup (reykjavikopen.com) has results for 20 games per round, presumably for games which were recorded automatically while they were in progress. [...] A similar interface producing the same information is on GAMMA Reykjavík Fischer Random Chess Memorial 2018 (chessbomb.com).
I used Chess-results.com to identify the top five boards per round, then used Chessbomb.com to create a PGN file of those games. That makes 45 games from the event (in fact, 46 games, because one game from round one defaulted after the first move). The following table shows the start position used in each round. The start position for round five was not recorded correctly at Chessbomb.com, so those games are effectively missing.
Rd Start Position (SP)
01 SP342 NRBKQBRN
02 SP592 BBRQNKRN
03 SP570 RNKNBBRQ
04 SP276 NBBRKNRQ
05 SP???
06 SP244 NBBRKQNR
07 SP095 NNRKRQBB
08 SP752 BBRKNNRQ
09 SP013 QNNBRKBR
The PGN file can be found at m-w.com/c960/blog/c96-ic31.pgn. If you find a problem with the file, please flag it using the comment section for this post.