Thanks, @griff!
These are user funds still on the network. Users have always been able to claim - more information on how to do it is here and within the documentation is the list of addresses. Also linked here.
The previous claiming process has been updated to make it easier to claim directly from the contract, as outlined in the documentation linked above.
OG post on EOL of PGN was published June 2024 and I published a recap in November 2024. 
@owocki Maybe with your socials you can post this thread again?