We have previously removed the official support for Linux 32 bit engine builds,
and now the time has come to remove that platform entirely from our builds (it has been available via bob.jar).
The main reason is that it is too cumbersome to maintain, and we see that the usage of 32 bit Linux platforms is very small nowadays (source: Steam Hardware Survey)
And, on the same note, we’re removing the 32 bit macOS builds from bob.jar as well since the earliest os version we support is macOS 10.7 (Lion), which is a 64 bit platform.
This change will happen soon, most likely in the next release.
You can find the list of supported engine platforms here