One of the Valve employees that the company will no longer officially support the Ubuntu distribution on Steam, starting with the release of 19.10, and will not recommend it to its users. The decision was made due to building 32-bit packages in Ubuntu 19.10, including 32-bit builds of libraries required to run existing 32-bit applications.
To run some games from Steam, the presence of 32-bit libraries is required. Valve is considering ways to minimize the damage caused by the end of support for Ubuntu 19.10+, but will shift its focus from now on to promoting another distribution. Which distribution kit will be offered as a recommended one will be announced later, since the final decision has not yet been made. It will probably be Debian, on the basis of which Valve develops its own SteamOS distribution, the last update of which was in April.
Recall that with problems due to the end of support for 32-bit x86 architecture in Ubuntu 19.10 also the Wine project, whose 64-bit edition is not yet ready for general use; and the GOG game delivery platform, which uses Wine to run many games. There are unconfirmed reports that Canonical is considering reversing the decision to discontinue i386 support or shipping multiarch packages with 32-bit libraries for 64-bit environments.
Source: opennet.ru