It is Debian based ( actually AntiX ) and so it has access to the full Debian universe ( 32 bit at least ) but has a curated list of applications well tailored to low-resource environments.
Some have said Debian is i686 only but this is what Debian says:
Debian, AntiX, DSL, MX, and Q4OS are all Debian based and so no longer support i586. What a shame.
Edit edit:
That said, this is a recent change ( Debian Bookworm ) and so Debian 11 ( Bullseye ) still supports Pentium. Debian 11.9 was just released in February.