I've not done this on linux, but a linux flash player can be found on archive.org:
Download page: https://web.archive.org/web/20201201042748/https://www.adobe.com/support/flashplayer/debug_downloads.html
Direct download: https://web.archive.org/web/20201125025810/https://fpdownload.macromedia.com/pub/flashplayer/updaters/32/flash_player_sa_linux.x86_64.tar.gz
You could try different dates, and maybe get v30 which most use because it's what the autosplitter was designed with. But since that's not relevant on linux, v32 is probably best.
(copied from discord announcement)
The migration of IL runs from Red Ball Category Extensions has been completed. ILs are now hosted on the Level leaderboard of each individual game in the Red Ball series. The RBCE IL board will remain up for a few days until everything has been archived, but no
