Games do not run natively, but through an emulator.
Modder and developer Markus95 has released a PSX 2 PS5 tool that allows games created for the first generation of PlayStation to be transferred to the PlayStation 5. The tool only works on jailbroken PlayStation 5.
PSX 2 PS5 is a converter that converts ISO files containing games from the first PlayStation into the PKG format used by the new console. Old games do not run natively on the PlayStation 5, but through an emulator.
From a PlayStation 5 perspective, the console launches Siphon Filter 3, but the player will see the game's actual title and icon; however, you can change them if you wish.
The tool also allows you to slightly modify old games: you can turn on the 60 Hz mode and activate splash screen skipping.
Games transferred to PlayStation 5 in this way can run on firmware no older than version 4.51.
This is interesting