In July of this year, we were talking here on the blog about one of the news that had generated discontent on the part of some with Ubuntu, since that Canonical had announced than for the current version of your system (Ubuntu 19.10) 32-bit architecture would no longer be supported.
Canonical was intended to completely stop package creation for i386 architecture (including abandoning the formation of multiarch libraries needed to run 32-bit applications in a 64-bit environment), but he reconsidered his decision after examining the comments made by the developers of Wine and especially Steam.
As a compromise, it was decided to guarantee the delivery of a separate set 32-bit packages with the necessary libraries to continue the operation of obsolete programs that remain only in 32-bit form or require 32-bit libraries.
The reason for the interruption of i386 architecture support is the inability to maintain packages at the level of other architectures compatible with Ubuntu, for example, due to the inaccessibility of the latest developments in security and protection against fundamental vulnerabilities such as Specter for 32-bit systems.
Maintaining a package base for i386 requires large resources for development and quality control, which are not justified due to the small user base (the number of i386 systems is estimated at 1% of the total number of installed systems).
That is why recently, Steve Langasek presented plans for future handling of 32 packages bits in Ubuntu. He summarized the results of a discussion with the community of a list of libraries for the i386 architecture, which is planned to be included to ensure compatibility with 32-bit applications in Ubuntu 20.04 "Focal Fossa".
Of the more than 30 thousand packages, about 1700 were selected, for which the formation of those 32-bit packages for the i386 architecture will continue.
As comments that for Ubuntu 20.04 Focal Fossa there will only be a limited number of packages 32-bit to maintain compatibility. These include, for example, Wine and the Steam client, through which the theme originally came to the table.
The list mainly includes libraries used in 32-bit applications still in use, as well as dependencies associated with these libraries. Besides that the packages that are considered Obsolete ones will be replaced by the most current stable versions and it is planned to save the dependencies used for testing the listed libraries, to cross-test the builds of the i386 library in the 64-bit system environment, thus simulating the environment that will be used under real conditions.
There are some other i386 binary packages whose sources have not been whitelisted yet, so they will be removed from the Ubuntu project in the near future completely from the package repository for Ubuntu 20.04.
Although as all this is still a preliminary analysis, mention that developers can be contacted for a while to request package compatibility.
This concerns both i386 package maintainers in official package sources, as well as those that maintain third-party software in a PPA (Personal Package Archive). The interested parts they should present their reasons for the existence of the 32-bit binary packages on the "ubuntu-release" mailing list or in the "# ubuntu-devel" chat room on Freenode. If these are valid, the packages will also be whitelisted and therefore Focal Fossa.
It still takes a bit until the planned mass removal of the i386 binaries: According to Langasek
“Initially, the project-specific infrastructure for package testing (“ autopkgtest ”) needs to be adapted to test 32-bit libraries on an amd64 host. This is also the environment in which 32-bit packages are generally used. "
If you want to know more about it, you can check the details of the discussion in the following link